NZ624526B2 - A milking system and a method for preventing detachment of a teat cup from a teat during a milking process - Google Patents

Abstract

Milking system and a method for preventing detachment of a teat cup from a teat of an animal during a milking process. The milking system comprises a milk line (1b, 1c, 2) connected to the teat cup (1a), a vacuum system able to apply at least two different vacuum levels to the teat cup (1a) and a measuring device (4) configured to measure the air flow in the milk line (1b, 1c, 2) during the milking process. The milking system comprises a control unit (5) configured to receive information about measured air flow values and to determine if the teat cup (1a) is about to be detached from the teat by comparing the measured air flow values (qa) with an acceptable value (qa1, ?q/?t), if the measured air flow values are not acceptable, to control the vacuum system such that it applies a higher vacuum level to the teat cup (1a) than the present vacuum level. asuring device (4) configured to measure the air flow in the milk line (1b, 1c, 2) during the milking process. The milking system comprises a control unit (5) configured to receive information about measured air flow values and to determine if the teat cup (1a) is about to be detached from the teat by comparing the measured air flow values (qa) with an acceptable value (qa1, ?q/?t), if the measured air flow values are not acceptable, to control the vacuum system such that it applies a higher vacuum level to the teat cup (1a) than the present vacuum level.

Description

A milking system and a method for preventing detachment of a teat cup from a teat during a milking process THE BACKGROUND OF THE INVENTION AND PRIOR ART The present invention relates to a milking system and a method for preventing ment of a teat cup from a teat during a milking process, wherein the milking system comprises a milk line connected to the teat cup, a vacuum system able to apply at least two ent vacuum levels to the teat cup and measuring device configured to measure the air flow in the milk line during the milking process.

During a milking process, vacuum is applied from a vacuum source to the teat cups in order to transport milk from the teat milk. In order to cups, via the milk line, to a storing device for transport the milk in the milk line, a small air flow needs to be created in the milk line. Usually, the teat cups or connected milk tubes comprise one or several small inlet openings or vents for ambient air ensuring such an air flow. A further object of the vacuum is to provide a suction force attaching the teat cups to the teats during a milking s. Such a connection between the teat cups and the teats is substantially air tight.

Undesired detachment of teat cups from the teats of an animal during a milking process is a problem. The teat cups may be detached for many reasons such as low vacuum in the teat cup, blocked air vents, restrictions in the short milk tubes, poor cluster alignment, worn milk tubes, uneven weight bution in 3O the cluster or be kicked off by the animals.

Thus, one reason for undesired teat cup detachment during a milking s is a low vacuum level in the teat cup. The vacuum level in the teat cups drops when the milk flow is high.

Consequently, there is an increased risk for undesired ment of teat cups during periods of the milking process when the milk flow is high. Some individuals in a herd of milking animals are more productive than the other. For these individuals, it is an increased risk that the teat cups fall off due to high milk flow during a part of the milking s. In order to reduce this risk, it is known to use milking systems able to apply two different vacuum levels to the teat cups, one high vacuum level and a reduced vacuum level. The high vacuum level is only used when the milk flow is very high during a milking process. 1O It is possible to use the reduced vacuum level during the whole milking process for most cows in a herd.

SUMMARY OF THE INVENTION The object of the present invention is to decrease the risk for undesired detachment of a teat cup during a milking process of an animal.

In one aspect, the invention es a milking system for preventing detachment of a teat cup from a teat of an animal during a milking process, wherein the milking system comprises a milk line ted to the teat cup, a vacuum system able to apply at least two different vacuum levels to the teat cup and a measuring device configured to measure the air flow in the milk line during the milking process, n the g system ses a control unit configured to e information about measured air flow values and to determine if the teat cup is about to be detached from the teat by comparing the measured air flow values with an acceptable value, and if the measured air flow values deviate from the acceptable value, to control the vacuum system such that it applies a higher vacuum level to the teat cup than the present vacuum level. The acceptable value may define a range of a parameter or one or several specific characteristics which are to be led for determining if a teat cup is about to be detached from a teat or not in view of measured air flow values. lfthe acceptable value is not fulfilled, the higher vacuum level is applied for preventing detachment of the teat cup. lf the vacuum level in a teat cup decreases for some reason, the suction force acting between the teat cup and the teat decreases. An air e into the teat cup may be the result and an increased air flow in the milk line.

An increased air flow through the teat cup results in its turn in a further decreased vacuum. When the vacuum level in the teat cup has decreased to a sufficient low level, the suction force between the teat cup and the teat is so low so that the teat cup falls off from the teat. y, this process occurs y within some seconds. Consequently, the airflow in a teat cup and in a connected milk line is a very relevant parameter indicating when a teat cup is about to be detached. According to the invention, the l unit applies a higher vacuum level to the teat cup as soon as it receives information indicating that a teat cup is about to be detached. The higher vacuum level increases the n 1O force between the teat cup and the teat. The air leakage is reduced and the teat cup is prevented from coming loose from the teat.

According to an embodiment of the invention, the control unit is configured to compare if a measured air flow value is higher than an acceptable value in the form of a maximum allowable air flow value and, if this is the case, to control the vacuum system such that it applies a higher vacuum level to the teat cup than the present vacuum level. If the air flow in the teat cup increases to a value above a maximum allowable value, there is a great risk that teat cup is about to be detached from the teat.

By applying a higher vacuum level to the teat cup, it is possible stop the sed air flow into the teat cup and prevent that the teat cup falls off.

According to an alternative embodiment of the invention, the control unit is ured to calculate a value of the air flow increase per unit time by means of measured flow values and if this calculated value is higher than an acceptable value in the form of a maximum allowable value of the air flow increase per unit time, to control the vacuum system such that it s a higher vacuum level to the teat cup than the present vacuum level. If the air flow in a milk line suddenly increases to a high value, it is a clear indication of an air leak and that the teat cup is about to be detached from the teat. The maximum allowable value may be a predetermined value, where the risk that teat cup is about to be detached from the teat is high. The d higher vacuum to the teat cup may here stop the accelerating air flow into the teat cup and t that the teat cup falls off.

According to another preferred embodiment of the invention, the control unit is configured to continue to receive measured air flow values after a higher vacuum level has been applied to the teat cup and to ine if the teat cup is still about to be detached from the teat by means of the measured air flow 1O values. In this case, it is possible to become aware if the applied higher vacuum to the teat cup stops air leakage into the teat cup or not. In case the air leakage into the teat cup increases further in spite of the applied higher vacuum level, a further higher vacuum level to the teat cup may be applied. In this case, more than two vacuum levels are used.

According to another preferred embodiment of the ion, the control unit is configured to determine, by means of the measured air flow values, when the teat cup no longer risks being detached from the teat. When the air flow in the milk line starts to drop or to decrease below a predetermined air flow value, the control unit may determine that the teat cup no longer is about to fall off. The control unit may be configured to control the vacuum system such that it restore the previous lower vacuum level to the teat cup when it determines that the risk is over. In this case, the milking process continues with the t applied vacuum level. Alternatively, the milking process continues with the higher vacuum level during the whole g process.

According to another red embodiment of the invention, the measuring device comprises a milk meter measuring the milk flow in the milk line. Different kinds of milk meters are used in most milking system in order to control the milking process in view of the milk flow. The teat cups are, for example, detached from the teats when the milk flow drops below a predetermined minimum value during a g process.

According to a preferred embodiment of the invention, the milk meter also includes components for measuring the air flow in the milk line. Milk meters measuring both the milk flow and the air flow are available on the market. In this case, the measuring device does not need to comprise a separate air flow meter and a separate milk meter in the milk line. ing to a preferred ment of the invention, the control unit is configured to determine if the teat cup is about to be detached from the teat by means of measured air flow values and measured milk flow values. A high milk flow reduces the vacuum in the teat cup and increases the risk that the teat cup falls off. In this case, it is possible to consider both the air flow and the milk flow to ine if a teat cup is about to be detached. The invention is particularly suitable to apply in milking system already using two vacuum levels in order to prevent that teat cups fall off at high milk flow. In this case, only small changes have to be performed.

The ion also es a method for preventing detachment of a teat cup from a teat during a milking s performed by a milking system, wherein the milking system comprises a milk line connected to the teat cup, a vacuum system able to apply at least two different vacuum levels to the teat cup and a measuring device configured to measure the air flow in the milk line during the milking process, the method comprising the steps of receiving information about measured air flow values, determining if the teat cup is about to be detached from the teat by comparing the measured air flow values with an acceptable value, and, if the measured flow air values deviate from the acceptable value, controlling the vacuum system such that it applies a higher vacuum level to the teat cup than the present vacuum level.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is now to be explained more y by means of preferred embodiments, which are disclosed as examples, and with reference to the attached drawings.

Fig.1 shows a milking system ing to an embodiment of the invention, 4o Fig. 2 shows a graph illustrating the milk flow as a function of the time during a milking process and 2012/051398 Fig. 3 shows a block diagram of a method according to an embodiment of the ion.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION Fig. 1 shows a milking member 1 in the form of a cluster. The cluster comprises four teat cups 1a. The teat cups 1a are connected to a claw 1c by means of a respective short milk tube 1b. A milk line 2 is configured to transport milk from the claw 10 to a main milk line 3. The main milk line 3 may receives milk from a plurality of milking members 1. The main milk line 3 is connected to a vacuum source applying a high vacuum level, which may be of about 50 kPa, to the milk line 3. The milk is transported in the main milk line 3 by means of the vacuum source to a not shown milk storage device in the form of a milk tank or the like. A milk meter 4 is arranged in the milk line 2.

The milk meter 4 is configured to measure the milk flow qm in the milk line 2. The milk meter 4 is also able to measure the air flow qa in the milk line 2.

A control unit 5 is configured to receive substantially continuously information from the milk meter 4 about the milk flow qm and the air flow qa in the milk conduit 2 during a g s. The vacuum system comprises a vacuum line 6. The vacuum level in the vacuum line is a high vacuum level, which line 6 and the main may be of about 50 kPa. Thus, the vacuum milk line 3 have the same high vacuum level. A vacuum regulating valve 73 is connected to the vacuum line 6 via a first vacuum conduit 8a. A control valve 7b is ed in the milk line 2. The control valve 7b is connected to the vacuum regulating valve 7a via a second vacuum conduit 8b. The milk line 2 comprises a first part 2a arranged upstream of the control valve 7b and a second part 2b arranged downstream of the control valve 7b with t to the intended milk flow direction in the milk line 2. The control valve 7b has a design such it es the same vacuum level in the first part of the 2a of the milk line as in the second vacuum conduit 8b.

The vacuum regulating valve 7a is settable in at least two different regulating positions. The vacuum regulating valve 7a is settable in a high vacuum position in which it does not reduce the vacuum in the vacuum line 6 at all. Consequently, the high vacuum level in the vacuum line 6 is d unchanged, via the first vacuum conduit 8a and the vacuum ting valve 7a, to the second vacuum conduit 8b and to the control valve 7b. in this case, the l valve 7b does not reduce the vacuum level in the first part 2a of the milk line 2 in relation to the vacuum level in the second part 2b of the milk line 2 and the main milk line 3.

The regulating valve 7avis settable in at least one vacuum vacuum reducing position in relation to the high vacuum position. When the vacuum regulating valve 7a is in the vacuum reducing position, a low vacuum level, which may be about 42 kPa, in the second vacuum conduit 8b in on to the high vacuum level of about 50 kPa. In this case, the control valve 7b reduces the vacuum level in the first part of the milk line 2a to the low vacuum level. Thereby, the vacuum level in the first part of the milk line 2a is lower than the vacuum level in the second part of the milk line 2b. The control unit 5 is able to set the vacuum regulating valve 7a in the high vacuum position and in the vacuum reducing position by means of information about measured air flow values milk flow values qm from the qa and milk meter 4 in the milk line 2.

During a milking process, vacuum is applied to the teat cups 1a.

A first object of the vacuum in the teat cup 1a is to transport the milk from the teat cup 1, via the milk line 2, to the main milk line 3. A second object of the vacuum is to provide a substantially air tight connection between the teat cups 1a and the teats such that the teat cup 1a obtains an attachment to a teat by means of a suction force. The vacuum level in the teat cups 1a during a milking process depends on, for example, the milk flow and air flow through the teat cup 1a. A high milk flow decreases the vacuum level in the teat cups 1a. A high air flow also ses the vacuum level in the teat cups 1a. if the vacuum level in a teat cup 1a decreases, such as for example of an extremely high milk flow, the suction force between the teat cup 1a and the teat decreases. There is here a risk that air starts to leak into the teat cup 1a. An air leakage ses the air flow in the milk line 1O 2 and the vacuum level in the teat cup 1a is further decreased. the vacuum level in the teat cup 1a becomes too low, the teat cup 1a falls off from the teat. Usually, this process occurs rapidly within some seconds.

Fig. 2 shows how the air flow may vary with the time during a milking process. The teat cups 1a are attached to the teats of a cow at the time to. Initially, an increased air flow qa may obtain in connection with the attachment of the teat cups 1a to the teats. When the teat cups 1a have been fixedly ed to teats, a small vely constant air flow qa is sensed by milk meter 4 in the milk line 2 during a large part of the milking process. The teat cup 1a or the short milk tubes 1b comprises one or several inlet openings for air in order to guarantee a relatively small air flow through the milk line 2 in order to ensure the transportation of milk. However, at the time t1, the air flow qa is suddenly increased. The air flow qa is here sed to a higher value than a maximum allowable air flow qa1. The control unit 5 determines, in view of received measured air flow values of the teat cups 1a is about to qa from the milk meter 4, that one be detached from a teat. The control unit 5 sets the regulating valve 7a in the high vacuum on such that a higher vacuum level is applied to the teat cups 1a than the present vacuum level. The higher vacuum in the teat cups 1a results in an increased n force between teat cups 1a and the teats.

Usually, this measure reduces the air leakage into the teat cup 1a and the air flow qa is relatively quickly decreased to the preceding air flow level. Due to the y applied higher vacuum level to the teat cup 1a at the time t1, the teat cup 1a ' was, in this case, prevented from being detached from the teat.

The initially used vacuum level may be restored in the teat cups 1a as soon as the control unit 5 receives ation indicating that air flow has been reduced to a normal flow level. During the following part of the milking process, a small vely constant air flow qa is sensed by the milk meter 4. The milking process is finished at the time t2 and the teat cups are removed from the teats. A temporarily increased air flow qa may occur when the teat cups 1a are removed from the teats.

Fig. 3 shows illustrating a process and a a block diagram method which may be med by the use of the milking system in Fig. 1. The process starts, at 12, and a milking animal in the form of a cow enters a milking stali or the like provided with a g member 1 of the milking system. The teat cups 1a are attached to the teats of the cow manually or by means of a milking robot. The control unit 5 receives substantially continuously information from the milk meter 4 about the milk flow qm and the air flow qa in the milk line 2. At 13, the l unit 5 compares measured miik flow values qm with a maximum milk flow value qm. If the milk flow qm is higher than a predetermined maximum milk flow value qm, the control unit 5 determines that there is a risk that the teat cups will be detached. The controi unit 5 sets the vacuum reducing valve 7a in the high vacuum position such that a high vacuum level is applied to the teat cups 1a; The process starts again at 12 and the control unit 5 es again information of measured milk flow values qm. At 13, the control unit 5 compares the measured milk flow values qm with the maximum milk flow value qm1. if the milk flow qm now is lower than the predetermined maximum milk flow value qm1, the control unit 5 determines that there is no risk that the teat cups will be detached from the teats. Mostly, the control unit 5 WO 89632 determines, at 13, that the milk flow qm is lower than the ble value The control unit 5 sets the maximum qm1. vacuum regulating valve 7a in the vacuum reducing position, at level to , and the l valve 7b provides a reduced vacuum the first part of the milk line 2a.

The milking process is continued at 16. The control unit 5 with a maximum compares here measured air flow values qa allowable air flow qa in the milk line 2 qa1. A too high air flow of the indicates in air leakage into a teat cup 1a and that one If the air flow teat cups 1a has d to detach from the teat. air flow qa1, the control qa is lower than the maximum ble unity 5 determines that no teat cup 1 has started to detach from a teat. in this case, the process starts again, at 12. Alternatively in combination, the control unit 5 may, at 16, calculate a value of the air flow increase per unit time Aqa/At and if this calculated value is higher than a maximum allowable such value Aqa1/At, to control the vacuum system such that it applies a higher vacuum level to the teat cup 1a than the present vacuum level. The unit time At is, for example, less than one second.

If the control unit instead determines, at 16, that air flow qa is higher than the maximum allowable air flow qa1, at least one of the teat cups 1 seems to have started being detached from the teat. The air leakage from the nding to this teat cup 1a results in a sudden and rapid increase of the air flow in the milk line 2. Something has to be done in order to t that the teat cup 1a comes loose from the teat. The control unit 5 sets, at 17, the vacuum regulating valve 7a in the high vacuum 3O position such that the control valve 7b applies the high vacuum level to the teat cups 1a. The suction force between the teat cups 1a and the teats increases. The air leakage between the teat cup 1a and the teat is reduced. The control unit 5 compares again, at 18, measured air flow qa values with the maximum allowable air flow qa1. If the measured air flow qa now is lower than the maximum allowable air flow qa1, the control unit 5 determines that the teat cups 1 will not come loose from the teat. The process starts again at 12.

If the air flow qa is still higher than the maximum allowable air flow qa1, the applied high vacuum has not reduced the air flow qa to a lower value than the maximum ble air flow value q“.

The control unit 5 compares, at 19, measured milk flow qm values with a m allowable milk flow qm1. A too low milk flow indicates that at least one of the teat cups 1a have been detached from a teat. If the milk flow qm is higher than the m allowable milk flow qm1, the control unit 5 determines that the milk line 2 still receives milk from all teat cups 1a. Thus, none of the teat cups 1 have fallen off yet. The process continues, at 17, with an unchanged high vacuum. If instead the milk flow qm is lower than the minimum allowable air flow qm1, the control unit 5 determines that one of the teat cups has been detached from a teat. In this case, it is possible to stop the milking process at 20.

The invention is not restricted to the described embodiments of the invention but may be varied freely within the scope of the claims. In the above mentioned embodiments, a milk line receives milk from four teat cups. It is of course possible to use and the one milk line for each teat cup and measure the air flow milk flow from each teat cup separately by means of a separate milk meter 4.

Claims (20)

WHAT WE CLAIM IS:

1. A milking system for preventing detachment of a teat cup from a teat of an animal during a g process, wherein the milking system comprises a milk line connected to the teat cup, a vacuum system able to apply at least two different vacuum levels to the teat cup and a measuring device configured to measure the air flow in the milk line during the milking process, wherein the milking system comprises a l unit configured to e 10 information about measured air flow values and to determine if the teat cup is about to be detached from the teat by comparing the measured air flow values with an acceptable value, and if the measured air flow values deviate from the acceptable value, to control the vacuum system such that it applies a higher vacuum 15 level to the teat cup than the present vacuum level.

2. A g system according to claim 1, characterised in that the control unit is configured to compare if measured air flow values are higher than an acceptable value in the form of a maximum 20 allowable air flow value and, if this is the case, to control the vacuum system such that it applies a higher vacuum level to the teat cup than the t vacuum level.

3. A milking system ing to claim 1 or 2, characterised in 25 that the control unit is configured to calculate a value of the air flow increase per unit time by means of measured flow values and if this calculated value is higher than an acceptable value in the form of a maximum allowable value of the air flow increase per unit time, to control the vacuum system such that it applies a 30 higher vacuum level to the teat cup than the present vacuum level.

4. A milking system according to any one of the preceding claims, characterised in that the control unit is configured to continue to 35 receive measured air flow values after a higher vacuum level has been applied to the teat cup and to determine if the teat cup is still about to be detached from the teat by means of the measured air flow values.

5. A milking system according to claim 4, characterised in that control unit is configured to determine by means of measured air flow values when the teat cup no longer risks being detached from the teat.

6. A milking system according to claim 5, characterised in that 10 control unit is configured to control the vacuum system such that it e the previous lower vacuum level to the teat cup when it determines that the teat cup no longer risks being detached from the teat. 15

7. A milking system according to any one of the preceding claims, terised in that the measuring device comprises a milk meter measuring the milk flow in the milk line.

8. A milking system according to claim 7, characterised in that the 20 milk meter also includes components measuring the air flow in the milk line.

9. A milking system according to claim 7 or 8, characterised in that the control unit is configured to ine if the teat cup is 25 about to be detached from the teat by means of measured air flow values and measured milk flow .

10. A method for preventing detachment of a teat cup from a teat during a milking process med by a milking system, wherein 30 the milking system comprises a milk line ted to the teat cup, a vacuum system able to apply at least two different vacuum levels to the teat cup and a measuring device configured to measure the air flow in the milk line during the milking process, the method comprising the steps of receiving ation about 35 measured air flow values, determining if the teat cup is about to be detached from the teat by comparing the measured air flow values with an able value, and, if the measured flow air values deviate from the able value, controlling the vacuum system such that it applies a higher vacuum level to the teat cup than the present vacuum level.

11. A method according to claim 10, characterised by that the step of comparing if a measured air flow value is higher than an acceptable value in the form of a maximum allowable air flow value, and, if this is the case, determining that the teat cup is 10 about to be detached from the teat.

12. A method according to claim 10 or 11, characterised by the step of ating a value of the air flow increase per unit time by means of measured flow values and if this calculated value is 15 higher than an acceptable value in the form of a maximum allowable value, determining that the teat cup is about to be detached from the teat.

13. A method according to any one of the preceding claims 10 to 20 12, terised by the step of continuing to e measured air flow values after a higher vacuum level has been applied to the teat cup and determining if the teat cup is still about to be detached from the teat by means of the measured air flow values. 25

14. A method according to claim 13, characterised by the step of determining by means of measured air flow values when the teat cup no longer risks being detached from the teat.

15. A method according to claim 14, characterised by the step of 30 controlling the vacuum system such that it restore the previous lower vacuum level to the teat cup when the teat cup no longer risks being detached from the teat.

16. A method according to any one of the preceding claims 10 to 35 15, characterised by the step of measuring the milk flow in the milk line.

17. A method according to claim 16, characterised by the step of ing the air flow and the milk flow by the same meter.

18. A method according to claim 16 or 17, characterised by the step of determining if the teat cup is about to be detached from the teat by means of the measured air flow values and measured milk flow values. 10

19. A milking system ntially as herein described with reference to and as shown in the accompanying drawings.

20. A method according to claim 10, substantially as herein described or exemplified with reference to the accompanying 15 drawings.