The invention also relates to an improved apparatus for carrying out said control method. comprising a measuring chamber provided with sensing means for determining the content of at least one component of the milk accumulated in said measuring chamber.

BACKGROUND OF THE INVENTION Development of automatic milking systems draws the attention to the nature of the physiology of the milk let down process. A good milking system must empty the udder as efficiently as possible, milk with a proper teat stimulation and not cause any damage to the teats. One way to satisfy these demands is to practice flow-controlled milking.

During the first seconds of milking as well as during the end of milking the milk flow is low, reaching a value of a few hundred grams of milk per minute. During the high flow phase the milk flow reaches values typically of 3-6 kg milk per minute.

The system vacuum level is usually kept at a constant level throughout milking.

However, the ideal situation is a milking machine which is adapted to the variation in milk flow during the complete milking and to the different udder quarters. A good example is the DuovacTM principle, which has a lower vacuum in the beginning and at the end of milking combined with a reduced pulsation speed. Another example is the MilkMasterTM principle, where also vacuum levels and pulsations are adjusted to the milk flow. A further example is the unique FloMaster milk-weighing principle, which combines high precision with high accuracy. The FIoMaster milk meter is designed for continuous in-line weighing of milk and comprises a fat sampling device, which can be attached to the milk meter. Compared to measuring the volume, weighing provides high accuracy and is independent of the air content in the milk. All of said principles are included in different concepts of the applicant.

In order to obtain a high milk yield in combination with good udder health it is essential to optimize the emptying-process of each udder quarter.

One problem in connection with today's milking systems is that the teat cups of the cluster are removed simultaneously from all quarters or teats of the udder, which may course overmilked front teats while the rear teats might be insufficiently or non- optimized milked. Under such circumstances of uneven udder-emptying the milk yield as well as the udder health are negatively influenced.

From EP 0 536 080 A2 is previously known a method for measuring liquid flow by measuring the transparency to electromagnetic radiation of the liquid flowing through one or more flow channels. The results produced by said method also provide information useful in indicating the actual composition of, for example milk, whose flow rate is being measured. Thus, it is possible to estimate different components of the milk, such as relative percentages of fat and protein, since these relative percentages influence the attenuation of the electromagnetic radiation by the milk.

The higher the percentage of fat in the milk. the lower will be the relative transparency of the milk to the radiation. and therefore the higher will be the attenuation resulting from the passage of the radiation through the milk. The electromagnetic radiation may be generated by means of light sources and detected by means of corresponding detectors in the one or all of the flow channels. Said light sources and detectors being selected to operate at different frequencies, so that the information received by their respective detectors would provide an indication of the relative composition of the milk then being measured, e. g., the relative percentage value of fat and protein. However there are no hints to the use of said value of fat content as an indicating means for the control of the emptying of each quarter of the udder.

From RU 2071056-C1 is previously known a determination device for fat and protein content in milk, which utilizes a prism lowered into a container with milk, so that the projecting reflecting face of the prism is completely immersed in the milk.

A coherent monochromatic light beam from a laser is focused by a lens onto the first face of the prism. A full internal reflection is obtained and a scattered light passes out through the second side face of the prism and is distributed to light detectors, converting the the light flows into electric signals. The values of the electric signals are obtained in an analogue-digital converter and passed to a control device, in which the contents of fat and protein are calculated. The device is merely used for the determination of fat and protein content of milk and milk products and there are no suggestions of using said signal values to control the milking process as to when a certain udder quarter is milked to an optimum.

SUMMARY OF THE INVENTION An object of the invention is to solve the described problems with regard to previously known apparatuses, by providing an improved method and apparatus for udder-emptying control.

The problems are solved by a method as initially defined, in which method the milk obtained from each udder quarter is supplied to a milk meter for indicating the milk flow and which milk meter is provided with a measuring chamber in which sensing means are arranged for the determination of the content of at least one certain component in the milk, characterized in that the fat content of the milk is continously monitored by said sensing means, which generates a signal corresponding to variations in said fat content over the time elapsed from the start of the milking process, and that the udder quarter in question has been emptied to a preset degree as soon as the signal indicates a value which exceeds a preset value.

A corresponding apparatus as initially defined is characterized in that the milk meter for indicating of the milk flow is provided with a measuring chamber in which a sensing means is arranged, said sensing means being capable of generating a signal corresponding to the fat content of the milk accumulated in said measuring chamber.

A milking system according to the invention is comprised of different management concepts which are known per se such as cow identification, measuring the milk yield, milk flow and milking time, by different sensors measure deviations in the milk composition and automatic attachment and removal of the cluster. It is desirable to create a more adapted milking system, a system which is adapted to the four individual udder quarters, as it is well known that each udder quarter has individual milk flow curves, individual milking times and flow rates. Therefore, in

order to create an optimal milking situation consideration has to be given to each individual quarter.

According to the invention, it is therefore advantageous to arrange the udder- emptying controi of each quarter in such a way, that the preset value. to be exceeded by the indicated signal value when the udder quarter in question has been emptied to a preset degree, is revised in respect of each quarter of each animal and in respect of the time elapsed after the previous milking. Further it is advantageous to arrange that simultaneously measured milk flow rates and values of fat content troughout the milking process are used for calculation of the total amount of fat produced for the udder quarter in question after a completed milking. Advantageously the milk accumulated in the measuring chamber is stirred by an agitator and the signal of the sensing means is generated by an infrared sensor, a spectrometer, or by a LED (Light-emitting diode) in combination with at least one photoelectric cell. Finally it is advantageous to arrange for the milk of the measuring chamber to be emptied into the milk meter by vacuum impact, compressed air or by a piston.

Preferred embodiments of the apparatus for carrying out the inventive control method comprise providing an agitator in the measuring chamber, the sensing means of which being comprised of an infrared sensor or a spectrometer or a LED (Light- emitting diode) in combination with photoelectric cells.

A further method as initially defined is characterized in that the fat content of the milk is continously monitored by said sensing means in the form of a prism located in the measuring chamber and completely immersed in the milk and illuminated by a laser beam light source, which generates a signal corresponding to variations in said fat content over the time elapsed from the start of the milking process and that the udder quarter in question has been emptied to a preset degree as soon as the signal indicates a value which exceeds a preset value.

A further apparatus as initially defined is characterized in that the milk meter for indicating of the milk flow is connected to a measuring container in which a sensing means in the form of a prism is arranged to be completely immersed in the milk and a laser beam light source for illuminating the prism at a predetermined angle. light detectors for converting the light flows into electric signals, which signals are corresponding to the fat content of the milk accumulated in said measuring container. Preferably the sensing means is combined with optical fibres for conveying the signals and are advantageously mounted at said optical fibres.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in more detail below by means of embodiments and with reference to the accompanying schematic drawings.

Fig. 1 is a general diagram of a milk meter provided with a measuring chamber with sensing means according to the invention, Fig. 2 is a graph showing a typical curve of the rise in fat percentage during milking, Fig. 3 is a partially cutaway side wiev of a first embodiment of the arrangement of the sensing means in the measuring chamber according to the invention, Fig. 4 is a partially cutaway side wiev of a second embodiment of the arrangement of the sensing means in the measuring chamber according to the invention, Fig. 5 is a diagram of a third embodiment of the arrangement of the sensing means in the measuring chamber according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Fig. 1 is a general diagram of a milk meter 2, one for each udder quarter, which is provided with a measuring chamber 4 in which sensing means 6 are arranged, in order to continuously determine the content of at least one certain component in the milk, namely the fat content. Preferred embodiments of said sensing means will be described later. The milk meter 2 is conventionally designed with a top 7 being provided with a milk inlet 8 for the milk delivered from the udder quarter in question, a surrounding wall 9 and a bottom 10, in which a milk outlet 11 is arranged for transfer of the milk further on in the milking system. As the volume measuring or weighing means of the milk meter 2 are comprised in the state of the art, they are not shown in the drawing for clarity reasons.

The measuring chamber 4 is attached to a lower part of the milk meter as appear from fig. 1 and is in communication with the milk meter via a sampling passage 12, located near the bottom 10. Further, the measuring chamber 4 is connected with the milk meter 2 by means of a, advantageously two times by 90 degrees curved, discharge pipe 14 as shown in fig. 1, which simultaneously serves as a component of and a suspension for the sensing means 6 near a first end 16 of said discharge pipe.

The measuring chamber 4 is like the milk meter assembled of a top 18 and a bottom 20 interconnected by a surrounding wall 22.

Said first end of the discharge pipe being located a distance d of 3-10 mm, prefereable 5 mm, from the bottom 20. A second end 24 of the discharge pipe is protruding into the milk meter 2 and directed towards the bottom 10 and outlet 11.

The cross section area of the discharge pipe 14 is advantageously at least twice the cross section area of the sampling passage 12, which is dimensioned in accordance

with established practice for milk samplers. An agitator in the form of an impeller 26 or the like is arranged near the bottom 20 of the measuring chamber 4 and is driven by a not shown driving means, e. g. an electric motor via a drive shaft 28. The sensing means 6 is supported by means of an energy source 30 and is arranged to transmit electromagnetic radiation across the first end 16 of the discharge pipe. The sensing means is also arranged to measure the attenuation of electromagnetic radiation by milk assembled in the measuring chamber 4 and discharge pipe 14 during the milking process. Thus, the relative transparency of the milk can be detected and the higher the percentage of fat in the milk, the lower will be the relative transparency of the milk to the radiation. Therefore the higher will be the attenuation resulting from the passage of the radiation through the milk. A detecting and storing unit 32 is connected to the sensing means and is provided with predetermined data for fat content and is arranged to evaluate, update and store data received from the sensing means. The energy source 30 and the unit 32 are both connected to the computer of the milking system via connection 34.

In a milking system (manual, semi-automatic or automatic, e. g. milking robots) it is advantageous to arrange the removing of the teat cups individually for each quarter.

The timing is essential and to secure that each udder quarter is emptied to its optimum before the teat cup is removed it is preferable to monitor and record the fat percentage continously during the milking process. The fat percentage rises during milking and is at its maximum when the milk in the alveolies is extracted. A graph representing this rise in fat percentage is relatively stable and uniform for an animal but varies for different animals. By a daily monitoring it is possible to observe deviations, which may be used as an indication or an alarm factor for an incorrect milking process.

Fig. 2 is a graph showing a typical curve of the rise in fat percentage during milking for one quarter of the udder. By means of the above described apparatus it is

advantageously arranged that the fat content of the milk is continously monitored..

The rise of the fat content during milking is represented bv random values A-D over the time elapsed from the start of the milking. The value D respresents a threshold value which indicates that the quarter in question is milked to an optimum. The value D is to be corrected in dependence of the milking intervals for the animal in question. etc). There is an option to measure the total fat production of each animal as the milk flow is measured by means of the milk meter.

Values for the milk flow in combination with the fat content over the time elapsed from the start of the milking for each quarter may be fed to the system computer, for calculation of a value for the total fat production of the animal in question.

A first embodiment of the arrangement of the sensing means 6 in the measuring chamber 4 according to the invention is disclosed in fig. 3. The discharge pipe 14 is prefereably made of a transparent material such as plastic and the part at the first end 16 of said pipe is on one side provided with a LED 36, which may be attached to the outside or the inside of said pipe part. The LED 36 is shown on the outside in the drawing and is connected to the energy source 30. Three photoelectric cells 38 are arranged in a similar mannner on the other side of the pipe part, which is opposite to the LED, and are electrically connected to the detecting and storing unit 32. Said pipe end 16 is located at a distance d from the bottom 20 of the measuring chamber.

A second embodiment of the arrangement of the sensing means 6 in the measuring chamber 4 according to the invention is disclosed in fig. 4. In this embodiment the discharge pipe 14 may be manufactured of a non-transparent material, e. g. plastic, however preferable a non-conducting material and the part at the first end 16 of said pipe is provided with a transmitter coil 40, which preferable may be attached to the outside of said pipe part. The transmitter coil 40 is connected to the energy source 30'. Two receiver coils 42'are arranged in a similar manner on each side of the transmitter coil, and are electrically connected to the detecting and storing unit 32'.

Said pipe end 16'is located at the distance d from the bottom 20 of the measuring chamber.

The first and second embodiments disclosed in fig. 3 and fig. 4 respectively have a similar function. When the milking process is started, milk passes through inlet 8 and further through sampling passage 12 and starts filling up the measuring chamber 4, where the milk is stirred by means of the impeller 26 to fascilitate an even rise of the fat percentage.

Then the milk passes through the space which originates from the distance d, by which the first end 16 of the discharge pipe is separated from the bottom 20 of the measuring chamber and the milk level rises, as shown by means of arrows in the discharge pipe 14. When the energy source 30 is activated, the LED starts emitting light through the milk assembled in the pipe end 16, and more or less light is transferred to the photoelectric cells 38 depending on the relative transparency of the assembled milk. Thus cells 38 generates signals of electric currents representative of the fat content of the milk, which signals are loaded into the detecting and storing unit 32 and further to the computer of the milk system for control of the removement of the teat cup in question. When the milking of an animal is completed, the measuring chamber 4 and the discharge pipe 14 are emptied by means of vacuum influence via the outlet 11. Due to the greate cross section area of the discharge pipe and the space between pipe end 16 and bottom 20 equal to distance d, the measuring chamber 4 is emptied into the milk meter outlet 1 land is ready for next animal.

Fig. 5 is a diagram of a third embodiment of the arrangement of the sensing means in the measuring chamber according to the invention, which is somewhat different from the above described embodiments. The sensing means 6"comprises a prism 44, which is completely immersed in the milk in the measuring chamber 4, and a coherent monochromatic light beam from a laser 46 is focused by a lens 48 onto the first face of the prism. A full internal reflection is obtained and scattered light passes

out through the second side face of the prism and along fibre-optic light guides 50 to light sensing means or lightdetectors 52-28, which preferably are located on the outside of the measuring chamber. Said light sensing means convert the intesities of light into electric signals, passed through amplifiers and converters 60-66 to the detecting and storing unit 32', in which the fat content in the milk is calculated and stored as in the earlyer embodiments. The energy source 30"is controlled by means of the milk system computer.

It may be preferable to arrange the photoelectric cells 38 also of the first embodiment outside the measuring chamber 4 and guide the light from the pipe end 16 to said cells by means of fibre-optic light guides.

While the invention has been illustrated by examples of embodiments using vacuum for emptying the measuring chamber, it is conceivable that also compressed air or a piston may be used for this purpose.

The above mentioned category of lactating animals comprise all such animals as cows, sheep, goats, horses, buffaloes etc.