SE0950206A1 - A cleaning system and method for cleaning teat cups on a rotary milking platform - Google Patents

Abstract

The invention relates to a cleaning system and a method for cleaning teat cups on a rotating milking platform. The cleaning system comprises a control unit (11) adapted to determine whether the teat cups (7) in the individual milking parlors (3) are to be cleaned before they are attached to a subsequent animal and to control a cleaning device (10) so that it cleans the teat cups (7) in an individual milking parlor (3) if it has been judged that they should be cleaned.

Description

35 not be continuously occupied during periods of low cow traffic to the platform. In reality, during certain periods of the day and especially at night, relatively few cows want to be milked.

During such low-loading periods, certain milking stalls may be vacant during a relatively long period. lf teat cups and milk conduits in a milking stall are not in use during a period of time, it is a risk that milk residues will dry and get stuck in the teat cups and the milk conduits. lt is thereby a risk that colonies of bacteria will start to grow on certain surfaces of the teat cups and the milk conduits.

SUMMARY OF THE INVENTION The object of the present invention is to achieve a rotary milking platform arrangement having a low consumption of cleaning liquid for cleaning the teat cups on the platform.

This object is achieved by a cleaning system for cleaning teat cups on a rotary milking platform of the kind initially defined, which is characterized in that the cleaning system comprises a control unit adapted to determine if the teat cups in the individual milking stalls are to be cleaned before being attached to a following animal and to control the cleaning device such that it cleans the teat cups in an individual milking stalls if they have been deemed to be cleaned. When the milking stalls on a rotary platform are used substantially continuously, the milk from the animals rinses the teat cups and the connected milk conduits in an effective manner. Consequently, it is not necessary to clean the teat cups between each milking process in a milking stall. According to the present invention, the teat cups in the milking stalls are only cleaned when they have to by, for example, hygienic reasons. Thereby, the numbers of cleaning treatments of the teat cups on the platform wilf be reduced. Thus the consumption of cleaning liquid, in the form of water or water with a detergent, is reduced in a corresponding manner. 10 15 20 25 30 35 According to an embodiment of the invention, the control unit is adapted to control the cleaning device such that it cleans the teat cups in an individual milking stall when the teat cups, after a last milking process, have not been used for any further milking process within a predetermined period. lf the teat cups are not used during a period, it is a risk that colonies of bacteria will start to grow in remaining milk residues in the teat cups and I the connected milk conduits. Preferably, the control unit is adapted to control the cleaning device such that it cleans the teat cups in an individual milking stall when the teat cups, after a last milking process, have not been used for any further milking process within a period corresponding to a predetermined number of revolutions of the milking stall on the platform. A complete milking process proceeds usually during one revolution on the platform. lt is therefore suitable to define the period without milking processer to a predetermined number of revolutions of the platform. In this case, the control unit has to count the numbers of revolutions at which the individual milking stall are vacant in succession.

According to an embodiment of the invention, the control unit is adapted to control the cleaning device such that it cleans the teat cups in an individual milking 'stall when the teat cups have been used during a predetermined numbers of milking processes. lf the teat cups are used substantially continuously, they are rinsed by the milk from the animals. However, if the teat cups in a milking stall have been used during a relatively long time and by a large number of animals, it is suitable to perform a cleaning treatment of the teat cups by a cleaning liquid. In this case, the control unit has to count the numbers of performed milking processes in the respective milking stalls after they have been cleaned the last time by the cleaning device. Advantageously, the control unit is adapted to control the cleaning device such that it cleans the teat cups in an individual milking stall when an unhealthy animal has been 10 15 20 25 30 35 milked by the teat cups. lf an animal has mastitis or if there is bacteria in the milk, there is a risk that a following animal in the milking position will be infected. In this case, the teat cups may be cleaned more carefully and with a bactericidal substance.

According to a further embodiment of the invention, the cleaning device may be arranged at the side of the platform. Thus, such a cleaning device is arranged beside of the platform and it not attached to the platform. Such a cleaning device may be used for cleaning the teat cups in all milking stalls. The cleaning device may be arranged on the outside of an outer edge portion of the platform or in the inside of an inner edge portion of an annular platform. Alternatively, the cleaning system comprises a cleaning device in each individual milking stall. ln this case, 'the teat cups may be cleaned when they are parked in a storing device in the respective milking stalls. The cleaning device may be adapted to clean the teat cups when the platform reaches a »predetermined rotational position. Preferably, the teat cups are cleaned in a rotational position of the platform when the milking stall is located between an exit passage where the animals leave the milking stall and an entrance passage where the animals enter the milking stall.

The above mentioned object is also achieved by a method for cleaning teat cups on a rotary milking platform of the kind initiatly defined, which is characterized by the steps of determining if the teat cups in the individual miiking stalls are to be cleaned before being attached to a following animal and to clean the teat cups in an individual milking stall by a cleaning liquid Ef they have been deemed to be cleaned. Thereby, the teat cups on the milking platform are only cleaned when they need to be clean. The number of cleaning treatments of the teat cups will be reduced. Thus, the consumption of cleaning liquid, which usually is water, is reduced in a corresponding manner. The method is especially preferable for rotary milking platforms located in regions where the water supply is restricted. 10 15 20 25 30 35 BRIEF DESCRIPTION OF THE DRAWINGS The present 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.

Fig 1 shows a voluntary milking arrangement provided with a cleaning system for cleaning teat cups on a rotary milking platform, _ shows an alternative cleaning system for cleaning teat cups on a rotary milking platform of a different kind and shows a flow chart of a method for cleaning teat cups on a rotary milking platform.

Fig 2 Fig 3 BRIEF DESCRIPTION OF PREFERRED EIVIBODIMENTS OF THE INVENTION Fig 1 shows a voluntary milking arrangement for milking of cows 1. The milking arrangement comprises- a rotary annular platform 2 having an inner edge portion 2a and an outer edge portion 2b.

The platform 2 rotates during operation around a vertical axis 2c. The platform 2 has an upper surface forming a support surface for the cows 1. A plurality of fence arrangements 4 are arranged on the upper surface of the platform 2. The fence arrangements 4 form milking stall 3 for receiving individual cows 1 in predetermined milking positions . In this case, the fence arrangements 4 have an essentially straight radial extension on the platform 2 between an inner end located at the vicinity of the inner edge portion 2a of the platform and an outer end located at the vicinity of the outer edge portion 2b of the platform. The fence arrangements 4 are arranged at equal intervals around the annular platform 2. An outer fence arrangement 5 is mounted around a main part of the outer periphery of the platform 2. The outer fence arrangement 5 prevents the cows 1 in the 10 15 20 25 30 35 milking stalls 3 step backward and out of the platform 2 during a milking process. i Each milking stall 3 is provided with a feeding trough 6 arranged in the vicinity of the inner periphery 2a of the platform. Each milking stall 3 is also provided with a set of teat cups 7 to be attached to the teats of a cow 1 standing in the respective milking stall 3. In this case, the set of teat cups comprise four separate teat cups 7. Each teat cup 7 is provided with a milk conduit 7a and a vacuum conduit 7b. Each milking stall 3 comprises a storing device 8 adapted to hold the teat cups 7 in a parked position when they are not in use. A base portion 9a of a robot arm 9 is arranged in a position outside the outer edge portion 2b of the platform 2. A cleaning device 10 is arranged in a position outside the outer edge portion 2b of the platform 2.

A control unit '11 is adapted to control a schematically shown drive mechanism 12 for driving the platform 2. The drive mechanism 12 may include a drive wheel mechanism, which is arranged in contact with a circular rail on the underside of the platform 2. A position sensor 13 is adapted to sense the rotational position of the platform 2 and to send a signal to the control unit 11 about the actual rotational position of the platform 2. The milking arrangement comprises an entrance passage 14 to the platform 2. The entrance passage 14 is provided with a detection sensor 15 and a movable gate 16. An exit area 17 is arranged in connection to the platform 2. The exit area 17 is entered by the cows 1 when they leave the platform 2. lf a cow 1 wanted to be milked, it walks to the entrance passage 14 leading to the rotary platform 2. The entrance passage 14 has a width such that only one cow 1 at a time can be located in a front position of the passage 14. The identification sensor 15 ident ifies the cow 1 when it arrives at the front position of the passage 14 and sends a signal to the control unit 11 with this 10 15 20 25 30 35 information. The gate 16 is in a closed position when the cow 1 arrives at the front position of the entrance passage 14. The control unit 11 receives substantially continuously information from the position sensor 13 about the actual rotational position of the platform 2. When a milking stall 3 arrives to a first rotational position pq, just in front of the gate 16, the control unit 11 opens the gate 16 and the cow 1 enters the platform 2.

The gate 16 is moved to its closed position as soon as the whole cow 1 is inside the milking stall 3. The feeding trough 6 attracts the cow 1 and facilitates the positioning of the cow 1 in the milking stall 3. The feeding troughs 6 may be movably arranged.

By setting the feeding trough 6 in a suitable position, it is possible to adjust the position of the cow 1 in the milking stall 3 to a desired milking position. In this case, the cows 1 are arranged in milking stalls on the platform 2 such that a longitudinal axis 1a of the cows forms an angle of about 90 degrees to the direction of motion 1b of the cows 1 on the platform 2. The cows 1 stand here in a radial direction on the platform with their heads at the inner edge portion 2a of the platform 2. ln these milking stalls 3, a back part of the cow 1 will be iocated at the outer edge portion 2b of the platform 2.

When the milking stall 3 with the cow 1 has rotated to a second rotational position pz, the robot arm 9 is activated and it fetches the teat cups 7 from the storing device 8 and attaches them to the cow 1. The platform 2 is driven with a slow speed such there is no problem for the robot arm 9 to compensate for the relative motions between the cow 1 on the platform 2 and the robot arm 9 during the attaching process of teat cups 7 to the cow 1. The milking process of the cow 1 starts when all teat cups 7 have been attached to the cow 1. A milk meter (not shown) supervises the milk flow during the milking process. As soon as the milk flow drops below a predetermined value, a removing device (not shown) removes the teat cups 7 from the teats of the cow 1. The milking process proceeds during nearly one 10 15 20 25 30 35 revolution on the platform 2 .lf the teat cups 7 have not been removed earlier, they are at least removed when the milking stall 3 reaches a thirteenth rotational position pm. ln the thirteenth rotational position P13, a treatment supplying device may spray a disinfec.ting medium or another kind of treatment medium to the teats of the cow 1 after that the teat cups 7 have been removed. Finally, when the milking stall 3 reaches a final fourteenth rotational position pm, the cow 1 leaves the milking stall 3 and enters the exit area 17. ln the fourteenth 'rotational position D14,' the cleaning device 10 is able to perform a cleaning treatment of the teat cups 7 in the storing device 8. The cleaning device may comprise a movable part which is moved to a position above the platform 2. The movable part of the cleaning device supplies a cleaning liquid to the teat cups in the storing device 8 The cleaning liquid may be water or water with a detergent. The milking stall 3 is thereafter again rotated to the first rotational position pi.

Especially, in regions with a restricted water supply, it is favorable to reduce the number of cleaning treatments of the teat cups 7 in the milking stalls 3 in order to reduce the water consumption. The milking arrangement above comprises a cleaning system adapted to fulfill this requirement. When all milking stalls 3 of a rotary platform 2 are used continuously, it is usually not necessary to clean or rinse the teat cup-s 7 between each milking process. In this case, milk residues from previously milked cows 1 are rinsed away by the milk flow through the teat cups 7 and the milk conduits 7a from a following cow 1 in the milking stall 3.

The cleaning system of the milking arrangement comprises the control unit 11 and the cleaning device 10. In this case, the cleaning system also comprises a number of sensors 13, 15, 26 adapted to provide the control unit 11 with necessary information. The control unit 11 adapted to determine if the teat cups 7 in the individual milking position 3 are to be cleaned 10 15 20 25 30 35 before being attached to a following animal and to control the cleaning device 10 such that it cleans the teat cups 7 in an individual milking stall 3 if they have been deemed to be cleaned. Consequently, the control unit 11 activates the cleaning device 10 only during circumstances when the teat cups 7 in a milking stall 3 need to be cleaned. ln other case, the cleaning device 10 does not perform a cleaning treatment of the teat cups 7 when the milking stalls 3 arrives to the final fourteenth rotational position p14. ln a milking arrangement with voluntary cow traffic, the cow flow to the rotary platform 2 varies during different periods of the day and night. Fig. 'L shows the milking arrangement during a period with poor cow traffic to the rotary platform 2. During certain periods of the day and especially at night, relatively few cows want to be milked. During such periods with poor cow traffic to the platform 2, certain milking stalls 3 may be vacant during a relatively long period. lf teat cups 7 and milk conduits 7a in a milking stall 3 are not used during a period, it is a risk that milk residues will be maintained in the teat cups 7 and the milk conduits 7a. lt is thereby a risk that colonies of bacteria will start to grow in the teat cups and the milk conduits.

Consequently, the teat cups 7 in a milking stall 3 which have not been used for a predetermined period need to be cleaned.

Due to this fact, the control unit 11 is adapted to receive information from the position sensor 13 when a vacant milking stall 3 arrives at the first rotationai position p1 of the platform 2 and from the second detection sensor 19 when a cow 1 enters the front position of the passage 18. The control unit 11 opens the gate 20 and the cow 1 enters the milking stall 3. The control unit 11 notes that this milking stall 3 is occupied by a cow. lf there is no cow 1 in the front position of the passage 18, when a vacant milking stall 3 arrives at the first rotational position pi the control unit does not open the gate 20. ln this case, the milking stall 3 will rotate in a vacant state during at least one revolution 10 15 20 25 30 35 10 on the platform 2. The control unit 11 notes that this milking position 3 is vacant. The control unit 11 is adapted to store information about when the individual milking stalls 3 on the platform 2 are occupied or vacant. lf a milking stall 3, after it has been occupied during at least one revolution, has been vacant during x numbers of revolutions in succession on the platform 2, the control unit 11 is adapted to control the cleaning device 10 such that it cleans the teat cups 7 in this milking stall 3. The number x of 'vacant revolutions in succession on the platform 2 may, for example, be three revolutions.

However, the teat cups 7 in the milking stalls 3 may be deemed to be cleaned during other circumstances. The cleaning device is adapted to clean the teat cups in an individual milking stall when the teat cups 7 have been used during a predetermined numbers y of milking processes, such as, twenty milking processes. When the teat cups 7 in a milking stall 3 have been used during a relatively long time and by a large number of cows 1, it is suitable to perform a cleaning treatment of the teat cups 7 by the cleaning device 10. ln this case, the control unit 11 controls the cleaning device 10 such that it cleans the teat cups 7 in the individual milking stalls 3 when they have been used during twenty milking processes. ln this case, the control unit 11 is also adapted to receive information from schematically shown detecting sensor 26 adapted to test the quality the milk from a cow 1 in a milking stall 3. lf the detecting sensor 26 detects that the milk is good, the milk collected in a milk receiver in the milking stall 3 is conducted to a milk tank. Otherwise, the milk in the milk receiver is refused or sent to a special milk tank. lf the milk detecting sensor 26 detects that the cow 1 has mastitis or lf there are bacteria in the milk, it is a risk that a following milked cow in the milking stall 3 will be infected. The milk detecting sensor 26 may also detect if the milk contains antibiotic or other medicines. tf the control unit 11 receives information from the detecting 10 15 20 25 30 35 11 sensor 26, indicating that an unhealthy cow 1 has been milked in a milking stall 3 or if the milk contains medicines, the cleaning device 10 is adapted to clean the teat cups 7 in the milking stall 3 which have been used during the milking process 1. ln this case, a more careful cleaning treatment of the teat cups 7 has to be performed. Preferably, the milking arrangement is stopped during a period of the night when the cow traffic to the milking arrangement is as low as possible. During this period, a complete cleaning treatment is performed of all components and milk conduits on the platform 2.

Fig 2 shows a part of an alternative milking arrangement for cows 1. Rotatable fence members 4 are here used for dividing the platform 2 into milking stalls 3 for receiving individual cows 1. By the use of rotatable fence members 4, it is possible to position the cows 1 very close together on the platform 2. Each of the fence members 4 is fixedly connected to a feeding trough 6. A rumprail 24 is arranged at an inner edge portion 2a of the platform 2. The rumprail 24 prevents the cows 1 from accidentally falling or stepping out of the platform 2. In this case, the cows 1 are arranged on the platform 2 such that the longitudinal axis 1a of the respective cows forms an angle to the direction of motion 1b of the cows 1 on the platform 2. which is less than 90 degrees. The cows 1 are here arranged in a herringbone pattern on the platform 2. The head of the cows 1 are in an outer radial position of the platform 2 when they are standing in the milking stalls 3 on the platform 2. An entry passage 16 and an exit area 17 for the cows 1 are located adjacent to each other at an outer edge portion 2b of the platform 2. A milking robot arm 9 is here arranged in a position inside the inner edge portion 2a of the platform 2. A teat cup storing device 8 are arranged on the platform 2. ln this case, the teat cup storing devices 8 with the teat cups 7, which are to be attached to a cow 1 standing in a milking position, are located in a positions on one side of said cow 1 and behind a cow 1 standing in an adjacent milking stall 3. When the cows 1 are 10 15 20 25 30 35 12 arranged in a herringbone pattern on a piatform 2, the above- mentioned space is normally empty. Therefore, it is very suitable to use this space for a storing device 8 holding the teat cups 7 in a parked position.

A cleaning device 18 is here arranged in each storing device 8 on the platform 2. ln this case, the cleaning device 18 comprises a so called back fiush valve 22 which is positionable in three positions by means of the control unit 11. When the teat cups 7 are attached to a cow 1, the back flush valve 22 is in a first milking position in which it connects a pulsation line 23b of the milking arrangement to the pulsation conduits 7b of the teat cups 7. ln the first milking position, the back flush valve 22 disconnects the milk conduits 7a of the teat cups 7a from a water line 23a of the milking arrangement. When the teat cups 7, for example, are attached or removed from a cow 1, the back flush valve 22 is positioned in a second position in which it both disconnects the pulsation conduits 7b of the teat cups 7 from the pulsation line 23b of the milking arrangement and the milk conduits 7a of the teat cups 7 from the water line 23a of the milking arrangement. ln a third cleaning position, the back flush valve 22 disconnects the pulsation conduits 7b of the teat cups 7 from the pulsation line 23a of the milking arrangement at the same time as it connects the water line 23b of the milking arrangement to the milk conduits 7a of the teat cups 7. ln this case, water will flow from the water line 23b to the milk conduits 7a and out of the respective teat cups 7. The water flow removes possible milk residues in the milk conduits 7a and in the teat cups 7 .

During operation of the milking arrangement the control unit 11 receives information from a position sensor 13 when a vacant milking stall 3 arrives to a first rotational position pi and from a detection sensor 19 when a cow 1 enters the front position of the passage 16. The control unit 11 opens the gate 16 and the cow 1 enters the milking stall 3. lf there is no cow 1 in the front 10 15 20 25 30 35 13 position of the passage 16, when a vacant milking stall 3 arrives to the first rotational position p1 the control unit 11 does not open the gate 16. In this case, the milking stall 3 will rotate in a vacant state during at least one revolution on the platform 2.

The control unit 11 stores information related to the occupation of cows 1 in the milking stalls 3. lf the teat cups 7 in a milking stall 3 after use in at least one milking process have not been used during a predetermined number of revolutions of the rotary platform 2, the control unit 11 is adapted to activate the cleaning device 18 such that it cleans the teat cups 7 in this milking position 3. When a cleaning treatment has to be performed, the control unit 11 sets the back flush valve 22 in a third cleaning position in this milking stall 3 such it connects the water line 23b of the milking arrangement to the milk conduits 7a of the teat cups 7.

Fig 3 shows a flow chart of an embodiment of a method for cleaning teat cups 7 on a rotary milking platform. The method starts at 27. The method starts when a milking stall 3 arrives to a final rotational position pH, pn on the platform 2. At 28, it is determined if the teat cups 7 in the milking stall have been used after they have been cleaned the last time. lf the milking stall 3 is occupied when it arrives to the last rotational position pm, pn, the teat cups 7 have of course been used. However, if the milking stall is vacant, stored data about the present milking stall 3 has to be taken into consideration for answering this question. lf the teat cups 7 have not been used during a milking process after they have been cleaned, they are clean and they will certainly not be cleaned again at 29. The method starts again, at 27, when the next milking stall 3 arrives to the final rotational position pH, pn on the platform 2. lf instead of the teat cups 7 have been used during at least one milking process after the last cleaning treatment, the method continues. At 30, information is received related to the health of the cow in the milking stall 3. lf an unhealthy cow 1 has been 10 15 20 25 14 detected in the milking stall 3, the teat cups 3 in the milking stall are cleaned at 31 Thereafter, the method starts again, at 27.

Normally, the cow is healthy and the method is continued at 32. lt is here checked if the milking stall 3 has been vacant during x number of revolutions on the platform 2. lf the teat cups 7 have not been used during x revolutions on the platform 2, there is a risk that colonies of bacteria will start to grow in milk residues from previously milked cows 1 in the teat cups 7. lf the teat cups 7 have not been used during x revolutions on the platform, a cleaning treatment of the teat cups 7 is performed at 31.

Thereafter, the method starts again, at 27.

Otherwise, the method is continued at 33. lt is here checked in how many milking processes the teat cups 7 have been used without being cleaned. lf the teat cups have been used during more than y milking processes, the teat cups 7 are deemed to be cleaned at 31. lf the teat cups have been used fewer than y milking processes, they will be not cleaned at 29. The method starts again at 27.

The invention is not restricted to the described embodiment but may be varied freely within the scope of the claims. In the above mentioned embodiments one of the three different conditions has to be fulfilled in order to start a cleaning process of the teat cups in a milking position. lt is of cause possible to use fewer conditions and other kinds of conditions in order to determine if the teat cups in the individual milking stalls are to be cleaned.

Claims (16)

10 '15 20 25 30 35 15 Claims A Cleaning system for cleaning teat cups of a rotary milking platform, wherein the rotary platform (2) comprises milking stalls adapted to house animals to be milked on the platform (2) and a set of teat cups (7) in each milking stall (3) to be attached to an animal in the milking stall (3) and wherein the cleaning system comprises at least one cleaning device (10, 18) adapted to clean the teat cups (7) by a cleaning liquid, characterized in that the cleaning system comprises a control unit (11) adapted to determine if the teat cups (7) in the individual milking statls (3) are to be cleaned before being attached to a following animal and to control the cleaning device (10) such that it cleans the teat cups (7) in an individual milking stall '(3) if they have been deemed to be cleaned. 2., A cleaning system according to claim 1, characterized in that the control unit (11) is adapted to control the cleaning device (10) such that it cleans the teat cups (7) in an individual milking stall (3) when the teat cups (7), after a last milking process, have not been used for any further milking process within a predetermined period. A cleaning system according to claim 2, characterized in that the control unit (11) is adapted to control the cleaning device (10) such that is cleans the teat cups (7) in an individual milking position (3) when the teat cups (7), after a last milking process, have not been used for any further milking process within a period corresponding to a predetermined number of revolutions of the milking stall (3) on the platform (2). A cleaning system according to claim 1, characterized in that the control unit (11) is adapted to control the cleaning device (10) such that it cleans the teat cups (7) in an individual milking position (3) when the teat cups (3) have been used during a predetermined numbers of milking processes. 10 15 20 25 30 35 16 A Cleaning system according to claim 1, characterized in that the control unit (11) is adapted to control the cleaning device (10) such that it cleans the teat cups (7) in an individual milking position (3) when an unhealthy animal (1) has been milked by the teat cups (7). A cleaning system according to any one of the preceding claims, characterized in that the cleaning device (10) is arranged at the side of the platform (2). A cleaning system according to any one of the preceding claims 1-5, characterized in that the cleaning system comprises a cleaning device (18) in each individual miiking stall (3). A cleaning system according to any one of the preceding claims, characterized in that the cleaning device (10) is adapted to clean the teat cups (7) when the platform has reached a predetermined rotational position (p14, pn). 9. A method for cleaning teat cups of a rotary milking platform, wherein the rotary platform (2) comprises milking stalls (3) adapted to house animals to be milked on the platform (2) and a set of teat cups (7) in each milking stall (3) to be attached to an animal in the milking stall (3), characterized by the steps of determining if the teat cups (7) in the individual milking stalls (3) are to be cleaned before being attached to a following animal (1) and to clean the teat cups (7) in an individual milking stali (3) by a cleaning liquid if they have been deemed to be cleaned. 10. A method according to claim 9, characterized by the step of cleaning the teat cups (7) in an individual milking stall (3) when i the teat cups (7), after a last milking process, have not been used for any further milking process within a predetermined period. 10 15 20 25 30 17 11. A method according to claim 10, characterized by the step of cleaning the teat cups (7) in an individual milking stall (3) when the teat cups (7), after a last milking process, have not been used for any further milking process within a period corresponding to a predetermined number of revolutions (x) of the milking stall (3) on the platform (2). 12. A method according to any one of claims 9-11, characterized by the step of cleaning the teat cups (7) in an individual milking stall (3) when the teat cups (3) have been used during a predetermined numbers of milking processes (y). 13. A method according to any one of claims 9-12, characterized by the step of Cleaning the teat cups (7) in an individual milking stall (3) when an unhealthy animal (1) has been milked by teat cups (7) ). 14. A method according to any one of the preceding claims 9 - 12, characterized by that the step of cleaning the teat cups by means of a cleaning device (10) arranged att the side of the platform (2). 15. A method according to any one of the preceding claims 9 - 13, characterized by the step of cleaning the teat cups (7) by means of a cleaning device (10) arranged on the platform (2) in the respective milking stalls ( 3). 16. A method according to any one of the preceding claims, characterized by the step of cleaning the teat cups (7) when the platform reaches a predetermined rotational position (pM).