Method and apparatus for monitoring a milking process

Abstract

A method of monitoring a milking process by a milking apparatus that includes a teatcup with a pulsation space and an airline to deliver varying levels of pressure to the pulsation space. The method includes: measuring airflow within the airline to obtain an indication of volume of displaced air within the pulsation space; comparing the volume with a reference value; and determining a connection parameter, indicating how the teatcup is connected to the teat, based on the comparison. The displaced air volume correlates to the extent the teat protrudes into the teatcup, thus providing information on how the teatcup is connected. Also provided is a milking system incorporating the method.

Claims

1. A control device for monitoring a milking process, the milking process performed by a milking apparatus including at least one teatcup configured to receive a teat of a milking animal and at least one airline configured to deliver varying levels of pressure to the teatcup, the device including: a flow sensor configured to measure airflow within the airline in order to obtain an indication of volume of displaced air within the teatcup; and at least one processor programmed to: compare the indication of volume of displaced air with a reference value; and determine a connection parameter relating to an extent of connection between the teat and the teatcup based on the comparison, wherein the flow sensor is provided in a part of the airline that is designed to only admit air to the teatcup.

2. The control device of claim 1, wherein the processor is configured to cause a robot arm to adjust a position of the teatcup relative to the teat on the basis of the connection parameter.

3. The control device of claim 1, wherein the flow sensor is a thermistor based flow sensor.

4. A robotic automatic milking implement configured to perform a milking process, the implement including: at least one teatcup configured to receive a teat of a milking animal; at least one airline configured to deliver varying levels of pressure to the teatcup; a robot arm configured to connect the teatcup to the teat; and a control device for monitoring the milking process, the device including: a flow sensor configured to measure airflow within the airline in order to obtain an indication of volume of displaced air within the teatcup; and at least one processor programmed to: compare the indication of volume of displaced air with a reference value; and determine a connection parameter relating to an extent of connection between the teat and the teatcup based on the comparison, wherein the flow sensor is provided in a part of the airline that is designed to only admit air to the teatcup.

5. The milking implement of claim 4, wherein the control device is configured to cause the robot arm to adjust a position of the teatcup relative to the teat on the basis of the connection parameter.

6. The milking implement of claim 4, wherein the flow sensor is provided in a part of the airline that is only intended to admit air to a pulsation space of the teatcup.

7. The milking implement of claim 4, wherein the flow sensor is provided downstream from a filter that filters drawn in ambient air.

8. The milking implement of claim 4, wherein the flow sensor is provided in a part of the airline that is isolated from any vacuum.

9. The milking implement of claim 4, wherein the flow sensor is a thermistor based flow sensor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The features and advantages of the invention will be appreciated upon reference to the following drawings, in which:

(2) FIG. 1 is a diagrammatic view of a milking device according to one embodiment of the present invention;

(3) FIG. 2 is a side view of a robot arm for use according to one embodiment of the present invention;

(4) FIGS. 3a-d illustrate extraction of milk using a milking device according to an embodiment of the present invention;

(5) FIG. 4 is a diagram illustrating pressure levels over time in the pulsation space;

(6) FIG. 5 schematic view of a flow sensor according to an embodiment of the present invention;

(7) FIG. 6 is an example of measurements of a airflow according to an embodiment of the present invention;

(8) FIG. 7 is an example of measured indications of volume in comparison with reference values according to an embodiment of the present invention; and

(9) FIG. 8 a diagrammatic sectional view of a pulsator detail of an embodiment of the present invention.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

(10) The following is a description of certain embodiments of the invention, given by way of example only and with reference to the drawings. FIG. 1 illustrates a milking device (generally indicated by arrow 1) for performing a milking process on a dairy animal. The device 1 includes four teatcups 2, 3, 4, 5, each connected to a pulsator system 6 by way of individual airlines, exemplified by airline 7 which is associated with teatcup 2. The vacuum line 8 for the pulsator system 6 is connected in a usual manner to a vacuum pump with balance tank.

(11) Each teatcup 2, 3, 4, 5 may be automatically connected and disconnected from a teat of a cow by means of a milking robot (as described with reference to FIG. 2).

(12) FIG. 2 illustrates a robot arm (generally indicated by arrow 20) for connecting a first teatcup 21 to a first teat 22, and a second teatcup 23 to a second teat 24.

(13) A position-determining device 25 detects the positions of the respective teats 22, 24 and teatcups 21, 23, and guides the teatcups 21, 23 to the teats 22, 24 such that vacuum attaches them.

(14) Retuning to FIG. 1, it should be appreciated that use of a robot arm is not intended to be limiting, as it is envisaged that the teatcups may be applied manually.

(15) The milk extracted by each teatcup 2, 3, 4, 5 is supplied via separate milking lines, exemplified by milking line 9 which is associated with teatcup 2, to a milk jar 10 and ultimately a milk tank.

(16) Each teatcup 2, 3, 4, 5 is provided with a flow sensor, exemplified by flow sensor 11, within their respective airlines—for example airline 7 of teatcup 2—configured to measure airflow within the airline in order to obtain an indication of volume of displaced air within the teatcups 2, 3, 4, 5.

(17) The indication of volume is sent from the sensor 11 to a processor 12. The processor 12 is also in communication with the pulsator system 6. It should be appreciated that the signals communicated from the sensor 11 and pulsator system 6 may include data identifying the respective sensor 11, pulsator within the pulsator system 6, and/or teatcup 2, 3, 4, 5.

(18) Data transmitted to the processor 12 may be stored in memory 13, together with other data used in calculations performed by the processor 12, as described hereinafter.

(19) FIGS. 3a, 3b, 3c, and 3d illustrate interaction of a dairy animal's udder 30 with a teatcup—for example, teatcup 2.

(20) The teatcup 2 includes a shell 31 and a liner 32, between which a pulsation space 33 is formed. The liner 32 is connected to the milking line 9, while the pulsation space 33 is connected by the airline 7 to a pulsator 34, which forms part of the pulsator system 6 of FIG. 1.

(21) The pulsator 34 acts as a valve, controlling connection of the airline 7 to vacuum 9 and atmospheric pressure 35.

(22) FIG. 4 illustrates a typical pulsation cycle, in which the pulsator 34 opens the airline 7 to vacuum 9. The vacuum levels build in phase A to a set vacuum level, which is maintained in phase B. The pulsator 34 then opens the airline 7 to atmospheric pressure 35. Pressure drops during phase C to atmospheric pressure in phase D.

(23) Turning to FIG. 3a, during phases A and B the pressure within the milking line 9 and pulsation space 33 is balanced, causing the liner 32 to be drawn away from the teat 36. This allows the vacuum of the milking line 9 to draw milk out of the teat 36.

(24) In FIG. 3b, during phases C and D the vacuum of the milking line 9 exceeds the pressure within the pulsation space 33, causing the liner 32 to collapse around the teat 36. This prevents milk from being extracted—providing a rest period for the dairy animal.

(25) As illustrated by FIG. 3c, the teatcup 2 may be incorrectly applied to the udder 30—either missing a teat or forming an inefficient connection. It may be seen that the liner 32 has completely collapsed.

(26) In FIG. 3d, the liner 32 does not collapse regardless of phase as there is no opportunity for the vacuum of the milking line 9 to act against the liner 32 due to the absence of a teat or other form of blockage.

(27) In each case, the flow sensor 11 is positioned in the airline 7.

(28) FIG. 8 diagrammatically shows a detail of a pulsator of an embodiment of the invention. It is shown that the airflow sensor 11 is provided in a part 35 of the airline where only atmospheric air is admitted, along arrow A. This air is filtered by filter 38, and optionally dried by a non-shown air drying device. Alternatively, the filter 38 may have drying properties. In the pulsator detail, there are provided an electromagnet 39 for driving a valve body 37 in a direction along double arrow B. In the position shown, the electromagnet 36 is energized and attracts valve body 37 in the upper position, thereby blocking ambient air admission. Now, vacuum is applied to the airline 7 via vacuum line 8. If the electromagnet 36 is de-energized, the valve body 37 will fall and/or be attracted by vacuum, into a lower position, thereby blocking vacuum line 8, and allowing admission of air into airline 7 via the part indicated by reference numeral 35. In the latter part, the airflow sensor 11 measures displaced air. This air has been cleaned and/or dried by filter 38. It is to be noted that other configurations and ways of operating pulsators are possible. The main point for this embodiment is the position of the airflow sensor 11 in a part that is only intended for admitting air, and not vacuum, into the airline 7 to the pulsation space of the teatcup.

(29) FIG. 5 illustrates one embodiment of the flow sensor 11. The sensor includes a thermistor RF, a bridge R0, R1, R2, op amp 50, and a power transistor 51.

(30) The op amp 50 continuously adjusts the flow of current, through the power transistor 51, to maintain its two inputs as equal. It follows that the voltage across the thermistor RF must be maintained at the same voltage across R2, and the thermistor RF current maintained at the level of the current through R1. However, since the current through R1 is proportional to the current through R0 (which has the same voltage drop as R1) and the current through R0 is determined by the voltage drop across R2 it may be seen that the resistance of the thermistor RF must be equal to that of R2, multiplied by the ratio of R1 to R0.

(31) As airflow increases, heat is transferred away from the thermistor RF, causing its voltage to rise. It follows that the op amp 50 output voltage increases, thus increasing the current through the power transistor 51. More power is available for the thermistor RF to dissipate in order to dissipate in order to maintain its temperature (and hence resistance) at a constant level. The output voltage at Vout provides an amplified version of thermistor RF voltage.

(32) FIG. 6 illustrates an output signal produced by the flow sensor 11 of FIG. 5.

(33) The graph shows Vout versus time in the scenario of FIG. 3d, where passage through the liner 32 is open. The waveforms which would be obtained under the conditions illustrated by FIGS. 3a and 3b, and 3c, would have a similar profile.

(34) FIG. 7 illustrates the results of readings obtained using the flow sensor 11 of FIG. 5 under several conditions, plotting Vout against the depth to which an artificial teat was inserted into the teatcup 2 in centimeters.

(35) The maximum voltage, minimum voltage, and average voltage over a pulsation cycle may be seen against the equivalent reading during the open liner 32 condition of FIG. 3d.

(36) Zero insertion corresponds to the condition of FIG. 3c.

(37) It may be seen that a strong correlation exists in each series between depth of teat insertion and volume of air displaced from the teatcup 2.

(38) The processor 12 may therefore determine a connection parameter by comparing the indication of volume of displaced air with a reference value. The reference value may be, for example: a predetermined value stored in the memory 13 connected to the processor 12; or an indication of volume measured prior to connection of the teatcup 2.

(39) The connection parameter may be used to determine whether the teatcup 2 is disconnected or improperly connected, or the length of the teat protruding into the teatcup 2.

(40) While there is a crossover in the readings at approximately 12 cm, in practice a teat of a dairy animal will not reach this depth.

(41) The processor 12 may determine that the teatcup 2: has fallen off (i.e. the connection parameter is effectively zero); or is blocked (i.e. the connection parameter is at a maximum).

(42) If either of these is the case, then it may control the robot arm 20 to reapply the teatcup 2 to the teat 36.

(43) If processor 12 determines that the teatcup 2 is connected, albeit incorrectly, or the teat is at too shallow a depth, the processor 12 may control the robot arm 20 to adjust the position of the teatcup 2 rather than attempting to relocate the teat 36 again.

(44) It is envisaged that the processor 12 may be configured to receive an identification of an individual dairy animal being milked, for example using a radio frequency identification tag reader. The processor 12 may cross reference this identification with individual animal data stored in the memory 13 in order to determine expected teat lengths for the animal and ensure optimal connection of the teatcups 2, 3, 4, 5.

(45) In addition to, or in place of, adjusting the position of the teatcups, the processor 12 may be configured to issue an alarm regarding a condition associated with the connection parameter obtained. This may be by way of display of text or lights at the milking device 1 or control module thereof, an audible alarm, a flag in software or any other suitable means known to a person skilled in the art.

(46) In manually operated systems, this will enable the timely reapplication or adjustment of the teatcup 2. In an automatic milking device, recordal of such alarms may allow for identification of ongoing faults requiring either recalibration of equipment, or repair or replacement of faulty components. For example, a fault condition such as a split liner 32 or disconnected hose will show an extreme response which may be identified as requiring attention of an operator.

(47) Further modifications in addition to those described above may be made to the structures and techniques described herein without departing from the spirit and scope of the invention. Accordingly, although specific embodiments have been described, these are examples only and are not limiting upon the scope of the invention.