WO2024191338A1

WO2024191338A1 - Milking system, computer-implemented method, computer program and non-volatile data carrier

Info

Publication number: WO2024191338A1
Application number: PCT/SE2024/050227
Authority: WO
Inventors: Anders Bertilsson; Magnus SOMMAR
Original assignee: Delaval Holding Ab
Priority date: 2023-03-14
Filing date: 2024-03-13
Publication date: 2024-09-19

Abstract

In a milking system, pressure sensors (121, 122, 123, 124) register pressure values (PT) representing pressure levels in connection piece air inlets (C1, C2, C3, C4) that provide known air flows into milk conduits (11, 12, 13, 14) while milking. During a non-milking period, the following steps are performed: valves (158, 191, 192, 193, 194) are controlled to connect the connection piece air inlets (C1, C2, C3, C4) with a reference pressure source (170) providing a system pressure level (PR); while the connection piece air inlets (C1, C2, C3, C4) are connected with the reference pressure source (170), test measures (Pc; P1, P2, P3, P4) are registered that represent pressure levels in the connection piece air inlets (C1, C2, C3, C4); respective differences are determined between the standard value (Ps) and the test measures (P1, P2, P3, P4); and based thereon, pressure offsets (Pos) are assigned that reflect respective estimated deviations from the system pressure level (PR) in the milk conduits (11, 12, 13, 14) during milking.

Description

Milking System, Computer-Implemented Method, Computer Program and Non-Volatile Data Carrier

TECHNICAL FIELD

The present invention generally concerns solutions for humane handling of dairy animals. Especially, the invention relates to a milking system according to the preamble of claim 1. The invention also relates to a computer-implemented method relating to the proposed milking system, a computer program and a nonvolatile data carrier storing such a computer program.

BACKGROUND

To avoid harming the dairy animals during milking, it is key that the pressure levels in the milking system be carefully monitored. The prior art contains various examples of solutions relating to this aim.

WO 2022/146 221 describes a milking system, comprising: teat cups, each connected to a respective milk evacuation tube; a vacuum pump; a milk tank; vacuum regulators, configured to control a vacuum pressure level prevailing in the teat cup; vacuum pressure sensors, each configured to measure vacuum pressure level prevailing under one of the teats; an animal identification sensor; a database; a processing device configured to: determine animal ID; extract data of each respective teat from the database; determine a teat specific vacuum pressure level at each teat; and generate a command to each vacuum regulator, to set the teat specific vacuum pressure level at each teat cup.

EP 1 668 980 discloses a method of milking an animal by means of a milking device with at least one teat cup having a pulsation space and a teat space, which teat space is connected to a vacuum source via a milk tube, the teat space and the milk tube forming a milking space. The method comprises successively a connection step, a milk-drawing step, a disconnection-preparing step and a discon- nection step, a pulsating pulsation vacuum being present in the pulsation space and a milking vacuum being present in the teat space during the milk-drawing step, the milking vacuum being lowered in the disconnection-preparing step. The disconnection step follows as soon as the vacuum level in the milking space has come below a threshold value in the disconnection-preparing step, said threshold value being adjustable per animal or per group of animals. A milking device provided with a robot for automatically connecting at least one teat cup to a teat of an animal, which teat cup comprises a teat space for containing a teat and a pulsation space for applying a milking motion by means of a pulsating pulsation vacuum, the teat space being connected via a milk tube to a vacuum source for generating a milking vacuum, the teat space and the milk tube forming the milking space, with a drawing-away device for drawing away the teat cup from the animal, with a vacuumlowering device for lowering the milking vacuum in the teat space, with a computer for activating the drawing-away device after the milking vacuum has been lowered, the milking space comprising a vacuum sensor for measuring the vacuum level and emitting to the computer a vacuum signal that is representative of the vacuum level. The drawing-away device is capable of being activated by the computer when the vacuum level in the milking space comes below a threshold value, said milking device comprising an automatic animal recognition device for emitting an animal recognition signal, and in that the threshold value is adjustable on the basis of the animal recognition signal.

In milking systems, a sub atmospheric pressure is used to transport the extracted milk from milking points to one or more milk-collecting containers. To enable this, ambient air must be allowed into each milk-transporting conduit via a respective air inlet arranged to provide a known flow of ambient air through a small-sized opening. Typically, the air inlet, in turn, is connected to the milk-transporting conduit via an air conduit and a connection piece air inlet into the milk-transporting conduit. During operation, milk particles may accumulate in and/or around the connection piece air inlet such that a smaller amount of air than intended is allowed into the milk-transporting conduit. As a result, the sub atmospheric pressure in the milk-transporting conduit will deviate from an intended pressure level therein. Typically, in such a case, the sub atmospheric pressure attains too high a magnitude. This, in turn, may lead to that the animals’ teats are harmed by an excessive pressure level prevailing in the teacups.

SUMMARY

The object of the present invention is to solve the above problem and offer a solution that avoids harmful pressure levels in the milk-transporting conduits of a milking system.

According to one aspect of the invention, the object is achieved by a milking system including at least one milking point, at least one pressure sensor and a controller. During milking, the at least one milking point is arranged to extract milk from an animal via at least one teatcup through at least one milk conduit to a milk-collecting container. The at least one pressure sensor is configured to register a pressure value representing a pressure level in at least one connection piece air inlet that is arranged to provide a known air flow in the at least one milk conduit during extraction of milk from the animal. During the extraction of milk, the controller is configured to obtain pressure values registered by the at least one pressure sensor. Moreover, during a non-milking period when no animal is connected to the at least one teatcup, the controller is configured to execute the steps:

[a] control at least one valve such that the at least one connection piece air inlet is placed in fluid connection with a reference pressure source providing a system pressure level in the milking system;

[b] while the at least one connection piece air inlet is in fluid connection with the reference pressure source, cause the at least one pressure sensor to register at least one test measure representing the pressure level in the at least one connection piece air inlet; [c] obtain the at least one test measure from the at least one pressure sensor;

[d] obtain a standard value of the system pressure level provided by the reference pressure source;

[e] determine at least one difference between the standard value and the at least one test measure; and based on the at least one difference

[f] assign at least one pressure offset reflecting an estimated deviation from the system pressure level in the at least one milk conduit during extraction of milk from the animal.

This milking system is advantageous because it enables monitoring of a pressure level that, in turn, indicates an actual pressure level prevailing at the teat tips of the animal during milking. Thus, it can be ensured that milking system does not expose the animal to any harmful pressure levels.

According to one embodiment of this aspect of the invention, the milking system includes a main pressure sensor arranged to register the standard value of the system pressure level provided by the reference pressure source. Alternatively, for example, the standard value of the system pressure level may be retrieved from a non-volatile data carrier and/or be entered manually. In either case, the controller obtains a reference for the at least one pressure offset.

According to another embodiment of this aspect of the invention, the reference pressure source is arranged in fluid connection with the milk-collecting container. Thus, it is straightforward to place the at least one connection piece air inlet in fluid connection with the reference pressure source.

According to yet another embodiment of this aspect of the invention, while the at least one connection piece air inlet is in fluid connection with the reference pressure source and the at least one test measure is registered, the at least one teatcup is arranged to prevent intake of air via any opening in the at least one teatcup into the at least one milk conduit. At the same time, the at least one milk conduit is arranged to receive air via at least one passive air inlet in fluid connection with the at least one connection piece air inlet. Consequently, air may be drawn from the at least one passive air inlet into the milk conduit when registering the at least one test measure.

According to still another embodiment of this aspect of the invention, the reference pressure source is instead arranged in fluid connection with a liquid pressure diverter when registering the at least one test measure. In such a case, when registering the at least one test measure, air may be drawn from the at least one teatcup into the milk conduit, such that the air passes through the at least one connection piece air inlet in a direction being opposite to the direction in the above embodiment.

Further preferably, while the at least one connection piece air inlet is in fluid connection with the reference pressure source and the at least one test measure is registered, the at least one teatcup is arranged to allow intake of air via at least one opening in the at least one teatcup into the at least one milk conduit. At the same time, at least one valve in the at least one milk conduit is closed to prevent a flow of air in the at least one milk conduit to be conveyed into the milk-collecting container. Thereby, it is ensured that the flow of air is exclusively directed to the liquid pressure diverter. Additionally, while the at least one connection piece air inlet is in fluid connection with the reference pressure source and the at least one test measure is registered, at least one valve is open to allow a flow of air to be conveyed through the at least one milk conduit.

According to another embodiment of this aspect of the invention the milking system contains a respective milk conduit configured to convey extracted milk from each of the at least one teatcup to the milk-collecting container. A respective pressure sensor is also arranged to register the pressure value representing the pressure level in each of the at least one connection piece air inlet in each of said respective milk conduits. As a result, a specific pressure offset may be determined for each of the milk conduits of the milking point. Naturally, this provides enhanced overall reliability in the detection of pressure anomalies.

According to a further embodiment of this aspect of the invention, the milking system includes a milk claw configured to collect milk extracted via the at least one teatcup. The milk claw is in further fluid connection with a milk conduit in which at least one connection piece air inlet is comprised. Here, a single pressure sensor is configured to register the pressure value representing the pressure level in the connection piece air inlet to a milk conduit being common for milk extracted from all the teats of the animal. Thus, any pressure anomalies may be detected in an uncomplicated and robust manner.

According to yet another embodiment of this aspect of the invention, during milking, the controller is configured to monitor the at least one pressure value registered by the at least one pressure sensor; and based thereon, estimate at least one pressure level in the at least one milk conduit using the at least one pressure offset. Consequently, throughout the milk extraction process, it may be ensured that any harmful pressure levels will be detected, and appropriate measures may be taken to avoid animal injuries.

According to still another embodiment of this aspect of the invention, the controller is configured to recurrently repeat the execution of the above steps [a] to [f] during at least one subsequent non-milking period. Thereby, the milking system may be held calibrated with respect to any variations in the pressure level in the milk conduit, so that these variations are kept within a tolerance range.

According to a further embodiment of this aspect of the invention, the controller is configured to adjust an occasion for a scheduled cleaning procedure for the at least one connection piece air inlet in response to the pressure offset. This means that a planned cleaning may either be advanced or postponed depending on the value of the pressure offset. In other words, cleaning may be effected when needed, and only when needed.

According to another embodiment of this aspect of the invention, the controller is configured to generate an alarm if the pressure offset exceeds a threshold level. Consequently, an operator may be notified of any substantial pressure deviations in the milk conduits.

According to another aspect of the invention, the object is achieved by a computer-implemented method for controlling a milking system with at least one milking point arranged to extract milk from an animal via at least one teatcup through at least one milk conduit to a milk-collecting container. It is further presumed that the milking system contains at least one pressure sensor configured to register a pressure value representing a pressure level in at least one connection piece air inlet that is arranged to provide a known air flow in the at least one milk conduit during extraction of milk from the animal. The method is performed in at least one processor during a non-milking period when no animal is connected to the at least one teatcup. The method involves the steps:

[a] controlling at least one valve such that the at least one connection piece air inlet is placed in fluid connection with a reference pressure source providing a system pressure level in the milking system;

[b] while the at least one connection piece air inlet is in fluid connection with the reference pressure source, causing the at least one pressure sensor to register at least one test measure representing the pressure level in at least one connection piece air inlet;

[c] obtaining the at least one test measure from the at least one pressure sensor;

[d] obtaining a standard value of the system pressure level (PR) provided by the reference pressure source;

[e] determining at least one difference between the standard value and the at least one test measure; and based on the difference

[f] assigning at least one pressure offset reflecting an estimated deviation from the system pressure level in the at least one milk conduit during extraction of milk from the animal.

The advantages of this method, as well as the preferred embodiments thereof, are apparent from the discussion above with reference to the proposed milking system.

According to a further aspect of the invention, the object is achieved by a computer program loadable into a non-volatile data carrier communicatively connected to a processing unit. The computer program includes software for executing the above method when the program is run on the processing unit.

According to another aspect of the invention, the object is achieved by a non-volatile data carrier containing the above computer program.

Further advantages, beneficial features and applications of the present invention will be apparent from the following description and the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is now to be explained more closely by means of preferred embodiments, which are disclosed as examples, and with reference to the attached drawings.

Figure 1 a shows a milking system according to a first embodiment of the invention, which is arranged to register test measures through a first approach;

Figure 1 b shows the milking system according to the first embodiment of the invention, which is arranged to register test measures through a second approach;

Figure 2a shows a milking system according to a second embodiment of the invention, which is arranged to re- gister test measures through the first approach;

Figure 2b shows the milking system according to the second embodiment of the invention, which is arranged to register test measures through the second approach;

Figure 3 shows a graph illustrating one example of how pressure offsets may be determined recurrently during a number of non-milking periods; and

Figure 4 illustrates, by means of a flow diagram, the general method according to the invention.

DETAILED DESCRIPTION

In Figure 1 a, we see a milking system according to a first embodiment of the invention. The milking system contains a milking point MP and a pressure sensor 120 associated to the milking point MP.

The milking point MP is arranged to extract milk from an animal via at least one teatcup, typically four T 1 , T2, T3 and T4 respectively. In the embodiment of Figure 1 , the teatcups T1 , T2, T3 and T4 are connected to a milk claw 135, which is configured to collect milk that has been extracted via the teatcups T 1 , T2, T3 and T4.

The milk claw 135, in turn, is in further fluid connection with a milk conduit 10 that for example may lead to a milk-collecting container 180 where the milk is temporarily stored before being fed to a milk tank (not shown). Preferably, a valve 195 is arranged on the milk conduit 10 to permit selective control of the milk transport from the milk claw 135 to the milk-collecting container 180.

As mentioned initially, ambient air must be allowed into the milk conduit 10 to enable forwarding of the milk through the milk conduit 10, preferably in the form of so-called slugs. Here, the milking system contains a passive air inlet 150 that is arranged to receive ambient air Atm via a small-sized opening providing a known air flow into an air conduit 20.

The air conduit 20, in turn, is in fluid connection with a connection piece air inlet C comprised in the milk conduit 10. The connection piece air inlet C thus constitutes an interface between a first fluid space in the air conduit 20 exclusively containing air, and a second fluid space in the milk conduit 10 containing milk and air at sub atmospheric pressure. The connection piece air inlet C is arranged to forward the known air flow of the passive air inlet 150 to the milk conduit 10.

During operation of the milking system, milk particles from the milk conduit 10 may accumulate in and/or around the connection piece air inlet C, such that the air flow into the milk conduit 10 is reduced. As a result, the pressure drop over the connection piece air inlet C will be higher than if the connection piece air inlet C were fully clean.

The pressure sensor 120 is configured to register a pressure value PT representing a pressure level in the connection piece air inlet C. To this aim, the pressure sensor 120 is arranged on the air conduit 20, for example near the passive air inlet 150. A controller 100 of the milking system is configured to obtain pressure values registered by the pressure sensor 120 during said extraction of milk, for instance to monitor the pressure level in the milk conduit 10 near the connection piece air inlet C. If, for instance, the pressure level in the milk conduit 10 is 42 kPa, and the pressure drop over the connection piece air inlet C is 4 kPa provided that it is unclog- ged/just cleaned, the pressure sensor 120 should register a pressure value PT equal to 38 kPa.

According to the first embodiment of the invention shown in Figure 1 a, during a non-milking period, i.e. when no animal is connected to the teatcups T1 , T2, T3 and T4, the teatcups T1 , T2, T3 and T4 are arranged to prevent intake of air via any opening in the at least one teatcup T1 , T2, T3 and T4 into the milk conduit 10, for example because the teatcups T1 , T2, T3 and T4 are arranged in a cleaning stand 130, the controller 100 is configured to execute the following steps.

First, the controller 100 is configured to control valves 155, 179 and 195, which valve 155 is arranged on a cleaning-fluid conduit 30 between the air conduit 20 and a liquid pressure diverter 160, which valve 179 is arranged on a connection conduit 177 between the milk container 180 and the liquid pressure diverter 160, and which valve 195 is arranged on the milk conduit 10 between the connection piece air inlet C and the milk container 180, such that the valve 155 is closed and the valves 179 and 195 are opened. This means that air may flow from the passive air inlet 150, through the air conduit 20, the connection piece air inlet C, the milk conduit 10, the milk tank 180, the connection conduit 177 and the liquid pressure diverter 160 in response to a sub atmospheric system pressure level PR provided by a reference pressure source 170, e.g. a vacuum pump, connected to the liquid pressure diverter 160.

Then, while the connection piece air inlet C is in fluid connection with the reference pressure source 170 as described above, the controller 100 is configured to cause the at least one pressure sensor 120 to register a test measure Pc representing the pressure level in the connection piece air inlet C.

Subsequently, the controller 100 is configured to obtain the test measure Pc from the pressure sensor 120. The controller 100 is also configured to obtain a standard value Ps of the system pressure level PR provided by the reference pressure source 170, either via a data connection from a pressure sensor 175 configured to register the system pressure level PR as illustrated in Figure 1 a, or in the form of a set value, or a value stored in a nonvolatile memory accessible by the controller 100.

Further, the controller 100 is configured to determine a difference between the standard value Ps and the test measure Pc. Said difference effectively expresses a sum of all pressure drops from the passive air inlet 150, and through the air conduit 20, the connection piece air inlet C, the milk conduit 10, the milk tank 180, the connection conduit 177 and to the liquid pressure diverter 160. Here, it can be assumed that the pressure drop over each component is essentially invariable except over the connection piece air inlet C, where the pressure drop may increase due to potential accumulation of milk as mentioned above.

In other words, variations in the difference between the standard value Ps and the test measure Pc constitutes a measure of how clogged the connection piece air inlet C has become.

Therefore, the controller is configured to assign at least one pressure offset Pos based on this difference. The pressure offset Pos reflects an estimated deviation from the system pressure level PR in the milk conduit 10 during extraction of milk from the animal.

According to one embodiment of the invention, the controller 100 is configured to monitor the at least one pressure value Pc, and based thereon estimate the pressure level in the milk conduit 10 using the at least one pressure offset Pos.

Figure 1 b again shows the milking system according to the first embodiment of the invention. Below, however, we will describe a second embodiment for determining the pressure offset Pos referring to Figure 1 b. All reference numerals in Figure 1 b that also occur in Figure 1 a designate the same units, components and variables as described above referring to Figure 1 a. In contrast to Figure 1 a, in Figure 1 b, the teatcups T1 , T2, T3 and T4 are arranged to allow intake of air via at least one opening in the teatcups T1 , T2, T3 and T4 into the one milk conduit 10, for example via a respective liner in which a teat is positioned during milking. Thus, the teatcups T1 , T2, T3 and T4 may hang freely.

Here, during a non-milking period when no animal is connected to the teatcups T1 , T2, T3 and T4, the controller 100 is configured to execute the following steps. First, the controller 100 is configured to control the valves 155, 179 and 195, such that the valve 155 is open and the valves 179 and 195 are closed. As a result, the connection piece air inlet C is placed in fluid connection with the reference pressure source 170 via the air conduit 20, the cleaning-fluid conduit 30 and the liquid pressure diverter 160, and a flow F of air in the milk conduit 10 is prevented from being conveyed into the milk-collecting container 180. Specifically, therefore, in addition to the passive air inlet 150, ambient air Atm may be drawn through the teatcups T1 , T2, T3 and T4, via the milk claw 135, the connection piece air inlet C, the air conduit 20, the cleaning-fluid conduit 30 and the liquid pressure diverter 160 to the reference pressure source 170. In other words, a flow of air F may pass the connection piece air inlet C in a direction opposite to the one in Figure 1 a. Nevertheless, of course, conclusions regarding a degree of clogging of the connection piece air inlet C can be made analogous to what is described above.

In particular, while the connection piece air inlet C is in fluid connection with the reference pressure source 170 according to the above, the controller 100 is configured to cause the pressure sensor 120 to register the test measure Pc representing the pressure level in the connection piece air inlet C.

Further, analogous to the embodiment described with reference to Figure 1 a, the controller 100 is configured to obtain the at least one test measure Pc from the at least one pressure sensor 120, obtain a standard value Ps of the system pressure level PR provided by the reference pressure source 170, and determine a difference between the standard value Ps and the test measure Pc.

Based on the difference, in turn, the controller 100 is configured to assign the pressure offset Pos reflecting the estimated deviation from the system pressure level PR in the milk conduit 10 during extraction of milk from the animal following the non-milking period.

For example, according to one embodiment of the invention, if the pressure offset Pos is found to exceed a threshold level Ptn, the controller 100 is configured generate an alarm A as explained below referring to Figure 3.

Figure 2a shows a milking system according to a second embodiment of the invention. All reference numerals in Figure 2a that also occur in Figures 1 a and/or 1 b designate the same units, components and variables as described above referring to Figures 1 a and/or 1 b. In short, Figure 2a illustrates how the pressure offset Pos is determined according to the first embodiment, i.e. analogous to Figure 1 a. In Figure 2a, however, each of the teatcups T1 , T2, T3 and T4 is directly connected to the milk container 180 by means of a separate milk conduit 11 , 12, 13 and 14 respectively enabling so-called quarter milking.

In Figure 2a, therefore, valves 191 , 192, 193 and 194 are equivalent to the valve 195 in Figure 1 a; air conduits 21 , 22, 23 and 24 are equivalent to the air conduit 20 in Figure 1 a; a parallel valve 158 is equivalent to the valve 150 in Figure 1 a; passive air inlets 151 , 152, 153 and 154 are equivalent to the passive air inlet 150 in Figure 1 a; pressure sensors 121 , 122, 123 and 124 are equivalent to the pressure sensor 120 in Figure 1 a; and connection piece air inlets C1 , C2, C3 and C4 are equivalent to the connection piece air inlet C in Figure 1 a.

Here, during a non-milking period when no animal is connected to the at least one teatcup T1 , T2, T3 and T4, the controller 100 is configured to control the parallel valve 158 to be closed and the valve 179 as well as the valves 191 , 192, 193 and 194 to be open. Consequently, each of the connection piece air inlets C1 , C2, C3 and C4 is placed in fluid connection with the reference pressure source 170 that provides the system pressure level PR in the milking system, i.e. via the milk conduits 11 , 12, 13 and 14, the milk container 180, the connection conduit 177 and the liquid pressure diverter 160.

Then, while the connection piece air inlets C1 , C2, C3 and C4 are in fluid connection with the reference pressure source 170, the controller 100 is configured to cause the pressure sensors 121 , 122, 123 and 124 to register a respective test measure Pi , P2, P3 and P4 representing the pressure level in the connection piece air inlets C1 , C2, C3 and C4 respectively.

Analogous to the above, the controller 100 is configured to obtain the test measures Pi , P2, P3 and P4 from the pressure sensors 121 , 122, 123 and 124; and obtain the standard value Ps of the system pressure level PR provided by the reference pressure source 170.

In further analogy to the above, the controller 100 is configured to determine a respective difference between the standard value Ps and each of the test measures Pi , P2, P3 and P4 respectively, and based thereon, assign respective pressure offset Pos reflecting an estimated deviation from the system pressure level PR in each of the milk conduits 11 , 12, 13 and 14 during extraction of milk from an animal being milked by the milking system in a later milking session.

Figure 2b shows the milking system according to the second embodiment of the invention, which is arranged to register test measures through the second approach. All reference numerals in Figure 2b that also occur in Figures 1 a, 1 b and/or 2a designate the same units, components and variables as described above referring to Figures 1 a, 1 b and/or 2a. In short, Figure 2b illustrates how the pressure offset Pos is determined according to the second approach, i.e. analogous to Figure 1 b, however with separate milk conduits 11 , 12, 13 and 14 directly connected to the milk container 180 as in Figure 2a, such that quarter milking is enabled.

Here, during a non-milking period when no animal is connected to the teatcup T1 , T2, T3 and T4, the controller 100 is configured to execute the below steps.

First, the controller 100 is configured to control the parallel valve 158 and the valves 191 , 192, 193, 194 and 179, such that the parallel valve 158 is open and the valves 191 , 192, 193,194 and 179 are closed. Thus, the connection piece air inlets C1 , C2, C3 and C4 are placed in fluid connection with the reference pressure source 170 providing the system pressure level PR in the milking system via the air conduits 21 , 22, 23 and 24, the cleaning-fluid conduit 30 and the liquid pressure diverter 160.

Then, while the connection piece air inlets C1 , C2, C3 and C4 are in fluid connection with the reference pressure source 170, the controller 100 is configured to cause each of the pressure sensors 121 , 122, 123 and 124 to register a respective test measure Pi, P2, P3 and P4 representing the pressure level in the connection piece air inlets C1 , C2, C3 and C4 respectively.

The controller 100 is further configured to obtain the test measures Pi , P2, P3 and P4 from the pressure sensors 121 , 122, 123, 124 and obtain a standard value Ps of the system pressure level PR provided by the reference pressure source 170, for example via a data connection from the pressure sensor 175 as illustrated in Figure 2b, or in the form of a set value, or a value stored in a non-volatile memory accessible by the controller 100.

Subsequently, the controller 100 is configured to determine a respective difference between the standard value Ps and each of the test measures Pi , P2, P3 and P4. Based on these differences, in turn, the controller 100 is configured to assign a respective pressure offset Pos reflecting an estimated deviation from the system pressure level PR in each of the milk conduits 11 , 12, 13 and 14 during extraction of milk from the animal, i.e. in a later milking session.

Figure 3 shows a graph illustrating one example of how a series of pressure offsets Pos may be determined recurrently during a number of non-milking periods. In Figure 3, the vertical axis reflects a magnitude of the pressure offset Pos and the horizontal axis designates different time instances when the pressure offset Pos has been determined according to any of the above-described embodiments. Specifically, it is presumed that a first pressure offset Pos is determined at a first point in time ti. Thereafter, the pressure offset Pos is also determined at points in time t2, ts, t4, ts, te, t? and ts during non-milking periods when no animal is connected to the teatcups T1 , T2, T3 and T4. Preferably, the first pressure offset Pos is determined shortly after completing a cleaning session as a reference value designating a condition where none of the connection piece air inlets C, C1 , C2, C3 or C4 is expected to contain any milk residues that may impair the flow of air there through.

The subsequently determined values of the pressure offset Pos at t2, ts, t4, ts, te, t? and ts may be based on measurements made at any time instance during non-milking periods, i.e. whenever suitable given the operation of the milking system. Hence, the time instances t2, ts, t4, ts, te, t? and ts may or may not be equidistant.

According to one embodiment of the invention, the controller 100 is configured to generate an alarm, if the pressure offset Pos exceeds a threshold level Pth. Namely, this may indicate that the connection piece air inlet associated with the pressure offset Pos value in question is clogged, or at least has an excessively restricted opening for receiving input air.

Typically, there is an in-advance established schedule specifying when the milking system shall undergo a cleaning procedure. To avoid risk cleaning the milking system too seldom, it is common practice that the schedule prescribes fairly frequent cleaning occasions. Many of the cleaning procedures are therefore performed prematurely, i.e. before cleaning is actually needed. Consequently, cleaning fluids and water are wasted, and there is an unnecessary downtime for the milking system.

According to one embodiment of the invention, therefore, the controller 100 is configured to adjust at least one occasion for a scheduled cleaning procedure for one of more of the connection piece air inlets C, C1 , C2, C3 or C4 in response to the pressure offset Pos. Thus, for example, should the schedule prescribe cleaning at t4, and the pressure offset Pos value at ts shows a sufficiently low magnitude, the controller 100 may adjust the schedule so that the next cleaning is instead planned to occur at a later point in time, i.e. after t4. Of course, the controller 100 may equally well adjust the schedule so that an originally planned cleaning is scheduled at an earlier point in time. For example, this may be the result of the alarm A being generated.

The controller 100 preferably includes processing circuitry in the form of at least one processor 113 and a memory unit 115, i.e. a non-volatile data carrier, storing a computer program 117, which, in turn, contains software for making the at least one processor 113 execute the actions mentioned in this disclosure when the computer program 117 is run on the at least one processor 1 13.

In order to sum up, and with reference to the flow diagram in Figure 4, we will now describe the computer-implemented method according to the invention which is performed in at least one processor during a non-milking period when no animal is connected to the teatcups T1 , T2, T3 and T4.

In a step 410, at least one valve is controlled such that at least one connection piece air inlet of the milking system is placed in fluid connection with a reference pressure source providing a system pressure level in the milking system.

Then, in a step 420, while the at least one connection piece air inlet is in fluid connection with the reference pressure source, the at least one pressure sensor is caused to register at least one test measure representing the pressure level in the at least one connection piece air inlet. In a step 430, which may be executed before, in parallel with or subsequent to step 420, the standard value of the system pressure level provided by the reference pressure source is obtained.

Thereafter, in a step 440, at least one difference is determined between the standard value and the at least one test measure. Finally, in a step 450, at least one pressure offset is assigned based on the at least one pressure offset, which at least one pressure offset reflects an estimated deviation from the system pressure level in the at least one milk conduit during extraction of milk from the animal.

The process steps described with reference to Figure 4 may be controlled by means of a programmed processor. Moreover, although the embodiments of the invention described above with reference to the drawings comprise processor and processes performed in at least one processor, the invention thus also extends to computer programs, particularly computer programs on or in a carrier, adapted for putting the invention into practice. The program may be in the form of source code, object code, a code intermediate source and object code such as in partially compiled form, or in any other form suitable for use in the implementation of the process according to the invention. The program may either be a part of an operating system, or be a separate application. The carrier may be any entity or device capable of carrying the program. For example, the carrier may comprise a storage medium, such as a Flash memory, a ROM (Read Only Memory), for example a DVD (Digital Video/Versatile Disk), a CD (Compact Disc) or a semiconductor ROM, an EPROM (Erasable Programmable Read-Only Memory), an EEPROM (Electrically Erasable Programmable Read-Only Memory), or a magnetic recording medium, for example a floppy disc or hard disc. Further, the carrier may be a transmissible carrier such as an electrical or optical signal which may be conveyed via electrical or optical cable or by radio or by other means. When the program is embodied in a signal, which may be conveyed, directly by a cable or other device or means, the carrier may be constituted by such cable or device or means. Alternatively, the carrier may be an integrated circuit in which the program is embedded, the integrated circuit being adapted for performing, or for use in the performance of, the relevant processes.

Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

The term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components. The term does not preclude the presence or addition of one or more additional elements, features, integers, steps or components or groups thereof. The indefinite article "a" or "an" does not exclude a plurality. In the claims, the word “or” is not to be interpreted as an exclusive or (sometimes referred to as “XOR”). On the contrary, expressions such as “A or B” covers all the cases “A and not B”, “B and not A” and “A and B”, unless otherwise indicated. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

It is also to be noted that features from the various embodiments described herein may freely be combined, unless it is explicitly stated that such a combination would be unsuitable.

The invention is not restricted to the described embodiments in the figures, but may be varied freely within the scope of the claims.

Claims

1. A milking system comprising: at least one milking point (MP) arranged to extract milk from an animal via at least one teatcup (T 1 , T2, T3, T4) through at least one milk conduit (10; 11 , 12, 13, 14) to a milk-collecting container (180), at least one pressure sensor (120; 121 , 122, 123, 124) configured to register a pressure value (PT) representing a pressure level in at least one connection piece air inlet (C, C1 , C2, C3, C4) that is arranged to provide a known air flow in the at least one milk conduit (10; 11 , 12, 13, 14) during extraction of milk from the animal, and a controller (100) configured to obtain pressure values registered by the at least one pressure sensor (120; 121 , 122, 123, 124) during said extraction of milk, characterized in that, during a non-milking period when no animal is connected to the at least one teatcup (T1 , T2, T3, T4), the controller (100) is configured to execute the steps:

[a] control at least one valve (155, 158, 191 , 192, 193, 194, 195) such that the at least one connection piece air inlet (C, C1 , C2, C3, C4) is placed in fluid connection with a reference pressure source (170) providing a system pressure level (PR) in the milking system,

[b] while the at least one connection piece air inlet (C, C1 , C2, C3, C4) is in fluid connection with the reference pressure source (170), cause the at least one pressure sensor (120; 121 , 122, 123, 124) to register at least one test measure (Pc; Pi , P2, P3, P4) representing the pressure level in the at least one connection piece air inlet (C, C1 , C2, C3, C4),

[c] obtain the at least one test measure (Pc; Pi , P2, P3, P4) from the at least one pressure sensor (120; 121 , 122, 123, 124),

[d] obtain a standard value (Ps) of the system pressure level (PR) provided by the reference pressure source (170),

[e] determine at least one difference between the standard value (Ps) and the at least one test measure (Pc; Pi , P2, P3, P4), and based on said at least one difference [f] assign at least one pressure offset (Pos) reflecting an estimated deviation from the system pressure level (PR) in the at least one milk conduit (10; 11 , 12, 13, 14) during extraction of milk from the animal.

2. The milking system according to claim 1 , comprising a main pressure sensor (175) arranged to register the standard value (Ps) of the system pressure level (PR) provided by the reference pressure source (170).

3. The milking system according to claim 2, wherein the reference pressure source (170) is arranged in fluid connection with the milk-collecting container (180).

4. The milking system according to any one of the preceding claims, wherein, while the at least one connection piece air inlet (C, C1 , C2, C3, C4) is in fluid connection with the reference pressure source (170) and the at least one test measure (Pc; Pi , P2, P3, P4) is registered: the at least one teatcup (T1 , T2, T3, T4) is arranged to prevent intake of air via any opening in the at least one teatcup (T1 , T2, T3, T4) into the at least one milk conduit (10; 11 , 12, 13, 14), and the at least one milk conduit (10; 11 , 12, 13, 14) is arranged to receive air via at least one passive air inlet (150; 151 , 152, 153, 154) in fluid connection with the at least one connection piece air inlet (C, C1 , C2, C3, C4).

5. The milking system according to any one of claims 2 or 3, wherein the reference pressure source (170) is arranged in fluid connection with a liquid pressure diverter (160).

6. The milking system according to claim 5, wherein, while the at least one connection piece air inlet (C, C1 , C2, C3, C4) is in fluid connection with the reference pressure source (170) and the at least one test measure (Pc; Pi , P2, P3, P4) is registered: the at least one teatcup (T 1 , T2, T3, T4) is arranged to allow intake of air via at least one opening in the at least one teatcup (T1 , T2, T3, T4) into the at least one milk conduit (10; 1 1 , 12, 13, 14), and at least one valve (191 , 192, 193, 194, 195) in the at least one milk conduit (10; 11 , 12, 13, 14) is closed to prevent a flow (F) of air in the at least one milk conduit (10; 11 , 12, 13, 14) to be conveyed into the milk-collecting container (180).

7. The milking system according to claim 6, wherein, while the at least one connection piece air inlet (C, C1 , C2, C3, C4) is in fluid connection with the reference pressure source (170) and the at least one test measure (Pc; Pi , P2, P3, P4) is registered, at least one valve (155, 158) is open to allow a flow (F) of air to be conveyed through the at least one milk conduit (10; 11 , 12, 13, 14).

8. The milking system according to any one of the preceding claims, comprising: a respective milk conduit (11 , 12, 13, 14) configured to convey extracted milk from each of the at least one teatcup (T1 , T2, T3, T4) to the milk-collecting container (180), and the at least one pressure sensor comprises a respective pressure sensor (121 , 122, 123, 124) each configured to register the pressure value (PT) representing the pressure level in a respective one of the at least one connection piece air inlet (C1 , C2, C3, C4) in each of said respective milk conduits (11 , 12, 13, 14).

9. The milking system according to any one of claims 1 to 7, comprising: a milk claw (135) configured to collect milk extracted via the at least one teatcup (T1 , T2, T3, T4), which milk claw (135) is in further fluid connection with a milk conduit (10) in which at least one connection piece air inlet (C) is comprised, and the at least one pressure sensor comprises a pressure sensor (120) configured to register the pressure value (PT) representing the pressure level in the at least one connection piece air inlet (C).

10. The milking system according to any one of the preceding claims, wherein, during milking, the controller (100) is configured to: monitor the at least one pressure value (Pc; Pi , 2, 3, 4) registered by the at least one pressure sensor (120; 121 , 122, 123, 124), and based thereon estimate at least one pressure level in the at least one milk conduit (10; 11 , 12, 13, 14) using the at least one pressure offset (Pos).

11. The milking system according to any one of the preceding claims, wherein the controller (100) is configured to recurrently repeat (t2, ts, t4, ts, te, t?, ts) the execution of the steps [a] to [f] during at least one subsequent non-milking period.

12. The milking system according to any one of the preceding claims, wherein the controller (100) is configured to adjust an occasion for a scheduled cleaning procedure for the at least one connection piece air inlet in response to the pressure offset (Pos).

13. The milking system according to any one of the preceding claims, wherein the controller (100) is configured to generate an alarm (A) if the pressure offset (Pos) exceeds a threshold level (Pth).

14. A computer-implemented method for controlling a milking system comprising at least one milking point (MP) arranged to extract milk from an animal via at least one teatcup (T 1 , T2, T3, T4) through at least one milk conduit (10; 11 , 12, 13, 14) to a milkcollecting container (180), and at least one pressure sensor (120; 121 , 122, 123, 124) configured to register a pressure value (PT) representing a pressure level in at least one connection piece air inlet (C, C1 , C2, C3, C4) that is arranged to provide a known air flow in the at least one milk conduit (10; 11 , 12, 13, 14) during extraction of milk from the animal, which method is performed in at least one processor (113) and which method, during a non- milking period when no animal is connected to the at least one teatcup (T1 , T2, T3, T4) comprises the steps:

[a] controlling at least one valve (155, 158, 191 , 192, 193, 194, 195) such that the at least one connection piece air inlet (C, C1 , 20 C2, C3, C4) is placed in fluid connection with a reference pressure source (170) providing a system pressure level (PR) in the milking system,

[b] while the at least one connection piece air inlet (C, C1 , C2, C3, C4) is in fluid connection with the reference pressure source (170), causing the at least one pressure sensor (120; 121 , 122, 123, 124) to register at least one test measure (Pc; Pi , P2, P3, P4) representing the pressure level in the at least one connection piece air inlet (C, C1 , C2, C3, C4),

[c] obtaining the at least one test measure (Pc; Pi , P2, P3, P4) from the at least one pressure sensor (120; 121 , 122, 123, 124),

[d] obtaining a standard value (Ps) of the system pressure level (PR) provided by the reference pressure source (170),

[e] determining at least one difference between the standard value (Ps) and the at least one test measure (Pc; Pi , P2, P3, P4), and based on said difference

[f] assigning at least one pressure offset (Pos) reflecting an estimated deviation from the system pressure level (PR) in the at least one milk conduit (10; 11 , 12, 13, 14) during extraction of milk from the animal.

15. A computer program (117) loadable into a non-volatile data carrier (115) communicatively connected to a processing unit (113), the computer program (117) comprising software for executing the method according to claim 14 when the computer program (117) is run on the processing unit (113)

16. A non-volatile data carrier (115) containing the computer program (117) of claim 15.