Method and arrangement in milking system

A method and arrangement for monitoring the supply of cleaning liquid from a cleaning line to a milking system, where the milking system includes at least two milking stations and milk conduits, and the cleaning line includes supply conduits connectable to the milk conduits at the milking stations and arranged to apportion cleaning liquid to the milking stations, so that cleaning liquid flows through the milking stations. The method includes measuring a value of the flow of the cleaning liquid through the respective milking stations by a respective flow sensor and transferring the values of the measured flows to a control unit. The arrangement includes a first control unit and flow sensors and a respective flow sensor is adapted to measure a value of the flows of cleaning liquid through a respective milking station, and provide the values to the control unit.

FIELD OF INVENTION

The present invention relates generally to the cleaning of milking systems and especially to the supply of cleaning liquid to a milking system.

BACKGROUND

Modern milking systems comprise milking stations able to milk animals, such as cows, and transfer the milk to a storage tank, while waiting for transport to a dairy plant. The milk is a vulnerable food product with high demands for cleanliness and handling temperatures, and it is important to protect it from micro organisms and prevent chemical reactions. Thus, the equipment of such a milking system has to be cleaned regularly. A way to clean the equipment is to empty the system from milk and supply a cleaning liquid, by means of a cleaning liquid supply line, to the milking system.

In milking systems which comprises several milking stations there is a need to make sure that a sufficient amount of cleaning liquid is supplied to the equipment of each station. The Japanese patent document JP 2000-324970 illustrates such a system. To supply a sufficient amount of cleaning liquid to the teat cups of the milking stations, selector valves are provided to alternately supply cleaning liquid to the teat cups at a first and a second milk line, respectively. In this way cleaning liquid is not supplied to all milking stations at the same time and thus a larger amount of cleaning liquid can be supplied to each station.

It is desirable to be able to clean as many stations as possible at the same time, but it is difficult to determine how many that can be sufficiently cleaned at the same time, especially in large milking systems, so called large milking parlors, with many stations.

The above-described drawbacks and deficiencies of the prior art are overcome or alleviated by a method and an arrangement for monitoring the supply of cleaning liquid to a milking system.

SUMMARY OF THE INVENTION

According to the invention there is provided a method and an arrangement of monitoring the supply of cleaning liquid from a cleaning line to a milking system, where the milking system comprises at least two milking stations and milk conduits, and the cleaning line comprises supply conduits connectable to the milk conduits at the milking stations and arranged to apportion cleaning liquid to the milking stations, so that cleaning liquid flows through the milking stations.

The method includes measuring a value of the flow of the cleaning liquid through the respective milking stations by means of a respective flow sensor, and transferring said values to a control unit.

The arrangement comprises a first control unit and flow sensors and a respective flow sensor is adapted to measure a value of the flows of cleaning liquid through a respective milking station, and provide said values to the first control unit.

Thus, the supply is monitored and a sufficient amount can be provided. Also, an unnecessarily large consumption of cleaning liquid can be avoided. It will be appreciated that the invention is of particular value in milking installations having a large number of milking stations. A typical large milking parlor comprises from 20 to 40 milking stations in a row, and often installations are configured in double rows. The invention is applicable for even larger installations.

In one embodiment the first control unit comprises a display and is adapted to display the values, and the method includes displaying the values at the control unit, so that the operator can monitor changes in performance.

One embodiment of the method includes alarming when the value of a measured flow is below a predefined minimum value to avoid inadequate cleaning.

Preferably the arrangement comprises means for regulating the supply of cleaning liquid to the milking system as a response to the measured flow and the method includes the step of regulating the supply of cleaning liquid to the milking system as a response to the values of the measured flows.

The supply regulation can include temporarily closing the supply to some milking stations, so that the supply to other milking stations increases. The arrangement can comprise electronic shut-off valves for this purpose.

Another example of the supply regulation is to regulate so that the difference between the values of the flows through the at least two milking stations decrease. Thus the supply is balanced between the milking stations.

The flow regulation can include decreasing the flow through a milking station when the measured flow exceeds a predefined maximum value, avoiding unnecessary large consumption of cleaning liquid.

In a preferred embodiment of the arrangement, the flow sensors are constituted by milk meters arranged at the milking stations. The method in this embodiment includes measuring the flow with the milk meters at the milking stations, thus using the milk meters in the system also during the cleaning process.

In further embodiments the regulating means comprises flow limiting inserts, preferably adapted for insertion into the supply conduits of the cleaning line and/or valves, preferably arranged on the supply conduits of the cleaning system. Preferably, the valves are electronic valves, i.e. electronically controllable valves, and are, in the embodiment that includes milk meters, preferably arranged in the milk meters.

In a further embodiment the first control unit is adapted to control the electronic valves.

In a further embodiment the arrangement comprise a cleaning unit connected to the cleaning line, and preferably the first control unit is arranged in the cleaning unit.

Alternatively to arranging the first control unit in the cleaning unit, the first control unit is in one embodiment adapted to control a milking process and, preferably, also adapted to control the electronic valves. This embodiment can, alternatively, include a second control unit and the first control unit can be adapted to transfer the values to the second control unit, which second control unit is adapted to control the electronic valves. This embodiment can include a cleaning unit and the second control unit can be arranged in the cleaning unit.

Further preferred embodiments are defined by the dependent claims.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In the following a detailed description of preferred embodiments of the present invention will be given.

FIG. 1illustrates schematically the main parts of a milking system provided with cleaning equipment. The milking system comprises milking stations4A,B,C,D, where animals are milked. Milk is drawn through a milk line2to a milk container6by means of a vacuum produced by a vacuum source8. From the milk container6, the milk is pumped to a milk cooling tank16, by means of a milk pump10, via a milk conduit14. Milk meters20A,B,C,D and22(inFIGS. 2 and 3) are arranged at the milking stations4A-D for measuring the milk flow from the milking stations4A-D to the milk conduit, and these milk meters are communicatively connected to a control unit17and/or18, which monitors the flows and amounts of milk at the milking stations4A-D. A valve arrangement12is located between the milk pump10and the milk cooling tank16and is arranged to selectively connect the milk pump10to the milk cooling tank16or to a cleaning unit5, via a conduit9.

The cleaning unit5is part of the cleaning equipment, which comprises a cleaning line1for supplying cleaning liquid to the milking system, via branch conduits3A-D connectable to respective milking stations4A-D. The cleaning unit also comprises internal elements (not illustrated), such as water supply valves, a dosing pump for adding solvent to the cleaning liquid, a heating element for heating the cleaning liquid, so that cleaning can be performed in common ways such as using water, heated water and water with a solvent as cleaning liquid. The cleaning equipment is arranged so that, during cleaning, the cleaning liquid is supplied via the cleaning line1and apportioned by means of the branch conduits3A-D to the milking stations4A-D. Each branch conduit is connectable to a respective milking station4A-D, so that, during milking, the branch conduits3A-D are disconnected and, during cleaning, the branch conduits3A-D are connected to the respective milking station4A-D. The vacuum source is then used to draw the cleaning liquid through the milking system from the milking stations4A-D to the milk container6. From the milk container6it is pumped by the milk pump10via valve arrangement12back to the cleaning unit5. The cleaning liquid is then circulated through the system. The cleaning unit5is also connected to an outlet (not shown) for discharging used cleaning liquid.

As an alternative to the valve arrangement12, a hose connected to the milk pump10can be used, which hose can be moved between the milk cooling tank16and the cleaning unit5, so as to selectively connect the milk pump10to the cleaning unit5and the milk cooling tank16, respectively.

FIG. 1also illustrates examples on control units7,17,18for controlling the milking process, the cleaning process, and especially the monitoring of cleaning liquid.

Thus, in one embodiment, a milking control unit18controls the milking process and a cleaning control unit7, arranged in the cleaning unit5, controls the cleaning process. To control the arrangement and the monitoring of cleaning liquid the milk control unit18and the cleaning control unit7can be communicatively interconnected. The monitoring of the supply of cleaning liquid is performed by the milk meters20A-D,22inFIGS. 2 and 3, measuring the flow through each milking station4A-D and the result is transferred to the milking control unit18. The result of the measurements can then be used for regulating the supply of cleaning liquid. Suitable constructional features for monitoring and controlling the supply of cleaning liquid to the milking system will be further discussed when describingFIGS. 2 and 3below.

InFIG. 1is, however, also illustrated an alternative to using a milking control unit18for controlling milking and a cleaning control unit7for controlling the cleaning. A central control unit17is arranged to control the supply of vacuum, control the milk pump and monitor the milking stations. Communication connections are illustrated by dotted lines inFIG. 1, where the central control unit17receives information from the milking stations4directly or via the milking control unit18and/or the cleaning control unit7.

A somewhat simplified alternative for the milking process can be provided by using the control unit to monitor the milk flow, but not for controlling the milk pump10. The milk pump10can be controlled equipping the milk container6with level detectors and arranging the milk pump to be turned on and off depending on the level of milk in the milk container6as detected by the detectors.

For the cleaning process there is, preferably, a transfer of information between the milking system and the cleaning equipment, facilitating both monitoring and control of the supply of cleaning liquid. On way to achieve this is to use the illustrated central control unit17communicatively connected directly to both the milking system and the cleaning equipment. Another way is to use the illustrated milking control unit18to monitor the flow and transfer the information to the cleaning control unit7.

The monitoring is accomplished by measuring the flow of cleaning liquid supplied at the milking stations. This can be done by arranging flow sensors26A-D in the branching conduits3or using the milk meters4at the milking stations. Thus, instead of inactivating the milk meters and/or the milking control unit during cleaning, the flow of cleaning liquid through the milk meters is measured and the result is transferred to a control unit7,17,18, chosen so as to be suitable for use together with the chosen regulating means.

Regulation can be accomplished in many ways, one example is indicating, using an alarm function, when the supply is to low, and as a response to the alarm increase the flow. This increase can be accomplished by decreasing the flow in some conduits so as to increase it where the flow is too low.

FIG. 2illustrates parts of the connections between the cleaning line1and the milking stations4A-D at the milk line2. The milking stations comprise milk conduits2A-D connecting the teat cups24A-D to the milk line. During milking the teat cups24A-D are connected to the animals. During cleaning, illustrated in the figure, the teat cups24A-D are connected to the branch conduits3A-D of the cleaning line1, each of the branch conduits being provided with flow regulating means21A-D and flow sensors26A-D.

Examples on different regulating means are illustrated inFIG. 3, one at each milking station4A-D. It is, however, preferred, to use the same type of regulating means for the supply of cleaning liquid at every milking station.

Only one teat cup is illustrated for each station, but the number should correspond to the number of teats of the animal. Different means and measures for flow regulation are illustrated inFIG. 3, such as adjusting a handle valve25manually, choosing and inserting a flow limiting insert27into the supply branch conduits3, controlling an electronic valve23at the supply side, or electronically controlling valves in milk meters22that comprises such a controllable valve, at the milking station side. The regulating means is suitably chosen when choosing monitoring means. For example handle valves25are suitably used together with a display for an operator at the control unit, and the measured flows are displayed. Electronic valves23are suitably used together with a control unit monitoring the flow and being adapted to provide control signals as a response to the flows.

Milk meters20A-D,22are, for example, used to measure the flow of cleaning liquid and the result is transferred to the milking control unit18, comprising a display, where the result is displayed. Regulating can be performed manually by inserting flow limiting inserts27, for example inserts shaped like washers with openings of a size chosen in dependence of the desired flow, into the supply conduit. Regulating by means of inserts can for instance be done during installation of new equipment. Alternatively, the supply conduits are provided with handle valves25and the regulation includes adjusting the handle valves25manually.

In another embodiment, milk meters20A-D,22are used to measure the flow of cleaning liquid and transfer the result of the measuring to the milking control unit18, which is adapted to, during cleaning, pass on the received result to the cleaning control unit7in the cleaning unit5. The cleaning control unit7then regulates the supply of cleaning liquid by means of electronic valves23arranged in the supply conduits3A-D.

In another embodiment, milk meters22, comprising regulating valves22, are used to measure the flow of cleaning liquid and transfer the result of the measuring to a milking control unit, which is adapted to provide control signals as a response. Thus the milk meters22are used both for measuring and regulating, and the control unit7,17,18use measurements from several milk meters to obtain an overall control and provide control signals or instructions for each individual milk meter valve.

In other embodiments, flow sensors26A-D are arranged in the supply conduits3A-D and the measurements can be used by operators manually or by control units automatically in accordance with the invention.

The different types of regulating means22,23,25,27can be combined so that, for example, during installation of the cleaning equipment the monitoring is used to choose suitable flow limiting inserts27so that the flows through the milking stations are balanced, i.e. becomes equally strong. During operation of the system the supply of cleaning liquid is then controlled by, for example, monitoring the supply by means of milk meters22transferring measurements to a control unit18and regulation the supply by automatically controlling electronic valves in the milk meters22by transferring control signals from the control unit18to the milk meters22.

Also, the monitoring can track changes in the measurements between cleaning operations. The control unit can be adapted to alarm when deviations of the measurements increases and become larger than reference values since large deviations indicates changes in the system, possibly malfunctioning and the need for service in the system. Thus, the system is adapted to alarm when measured flows from successive cleaning operations differ more than a predefined threshold.

Preferred embodiments of a method and arrangement according to the invention have been described. A person skilled in the art realises that this could be varied within the scope of the appended claims.