AU2007263307B2

AU2007263307B2 - Device for detecting a flow of milk

Info

Publication number: AU2007263307B2
Application number: AU2007263307A
Authority: AU
Inventors: Reinhold Knoche; Juan Olmedo; Andreas Springer
Original assignee: GEA WestfaliaSurge GmbH
Current assignee: GEA Farm Technologies GmbH
Priority date: 2006-06-20
Filing date: 2007-06-19
Publication date: 2011-03-17
Anticipated expiration: 2027-06-19
Also published as: AU2007263307A1; DE102006028748A1; RU2009101388A; EP2028926A1; EP2028926B1; NZ573940A; DE102006028748B4; ES2401028T3; RU2445769C2; WO2007147555A1

Description

WO 2007/147555 PCT/EP2007/005380 Device for detecting a flow of milk The subject matter of the invention relates to a device for detecting a flow of milk flowing in a channel which 5 has an inlet and an outlet. At least two electrically conductive elements are provided inside the channel. Different embodiments and configurations of devices for detecting a flow of milk are known. Utility model 295 10 03 450 discloses a device having a through-flow chamber in which two electrodes are arranged. Such a device can be used, for example, to check a threshold value. The threshold value check forms a basis for controlling the milking operation. If, for example, a threshold value 15 is undershot, a milking cluster is removed. Another configuration of a device for detecting a flow of milk is previously known, for example, from EP 0 509 288 Al. This device also has a channel in which two 20 electrodes which are arranged at a distance from one another are provided. EP 0 509 288 also describes devices for detecting a flow of milk, in which the detection is carried out capacitively or optically. 25 A prerequisite for detecting the flow of milk according to EP 0 509 288 is that installation is effected in a section of a riser since the length of a milk stopper is detected. 30 Detection of the flow of milk and, in particular, determination of the quantity of milk are relatively problematic since milk can also flow in the channel in the form of a foaming liquid. The flow of milk may thus have a liquid phase and a foam phase, the conductances 35 of which are different. In order to solve this problem, DE-Al-37 37 607 has proposed a method for carrying out the measurement on foaming liquids, in which a measured value which depends on a parameter of the liquid is 2 respectively measured on the liquid in a vessel at a plurality of different levels. For this purpose, a reference measuring section which essentially contains degassed liquid is provided for the purpose of measuring the specific density of the milk at the different levels. Depending on whether a corresponding measured value, which is measured in air, 5 is greater than or less than the reference value obtained in the reference section, a numerical ratio corresponding to the ratio of the reference measured value to the measured value at each level or corresponding to the reciprocal of this ratio is formed for said level. In order to be able to carry this out, provision is made of a measuring chamber having a multiplicity of electrodes which are arranged on top of one another and form the 1o corresponding levels. The outlay on apparatus for configuring such a device and for evaluating the measurement results is relatively high. Object of the Invention is It is the object of the present invention to substantially overcome or ameliorate one or more of the disadvantages of the prior art. Summary of the Invention The present invention provides a device for detecting a flow of milk, having a 20 channel, which has an inlet and an outlet, and having at least two electrically conductive elements which are arranged at a distance from one another in the channel, wherein at least one element is essentially annular and at least one element is essentially pin-shaped, and wherein the channel has at least one chamber having a measuring unit for measuring the conductance of the milk, the chamber having an inlet opening upstream of which a 25 flow element is arranged. The profile of the conductance of the milk can be reliably determined with the aid of the measuring unit and the chamber. This profile allows conclusions to be drawn regarding the state of health of the milk-yielding animal. The conductance measurement also makes it possible to determine the foremilk. The conductance value of the foremilk 30 can be used to draw conclusions regarding possible mastitis of the milk-yielding animal. The chamber has an inlet opening. At least one flow element is arranged upstream of the inlet opening of the chamber. As a result of the flow element, the milk flows into the chamber without great turbulence. This configuration has the advantage that the device is suitable for detecting a flow of milk, in particular for determining quantities of milk in the 3s milk volumetric flow range of 0.0 to 9.0 1/min. This achieves a relatively high degree of 3 accuracy as regards the quantity of milk. This configuration according to the invention of a device for detecting a flow of milk results in a relatively simple design of the device. A relatively high degree of measurement accuracy is surprisingly achieved. The at least one pin-shaped element may have different cross-sectional shapes. In s this case, the cross section of the pin-shaped element may be polygonal, in particular triangular, square or hexagonal. It is also possible for the cross section to have an oval shape, in particular an essentially circular shape. It is not necessary for the pin-shaped element to have a cross- WO 2007/147555 PCT/EP2007/005380 -4 sectional area which is constant in the longitudinal direction of the element. It is also possible to design the element in such a manner that it has a cross section which varies over the length of the element. In 5 this case, the pin-shaped element may have a larger cross section in the region of at least one end than in the central region. In the pin-shaped element, the clear width of the element is smaller, preferably substantially smaller, than the length of the element. 10 The pin-shaped element is preferably composed of at least one electrically conductive material. The material may be a metal and/or an electrically conductive plastic. 15 The device according to the invention for detecting a flow of milk can also be used to detect milking cups which have been knocked off or a milking cluster which has been knocked off. Since the flow of milk is 20 permanently detected using the electrodes, a sudden change in the flow of milk can also be detected promptly. If a milking cup or the entire milking cluster is knocked off, the flow speed in the channel increases as a result of the air which flows in. In 25 addition, it can be concluded from the sudden change in the conductance or conductivity of the fluid flowing in the channel that at least one milking cup or the entire milking cluster has been knocked off. 30 In order to isolate the at least two electrically conductive elements from one another, it is proposed that the channel have at least one section between two adjacent elements which is composed of an electrically non-conductive material. One configuration of the 35 device in which the channel is formed from at least one electrically non-conductive polymer is particularly preferred.

WO 2007/147555 PCT/EP2007/005380 -5 One configuration in which the at least one annular element is an integral part of the channel is particularly preferred here. The annular element should 5 preferably be arranged in such a manner that the annular element has an internal cross section which essentially corresponds to an internal cross section of the channel. If the channel has a circular cross section, the internal diameter of the annular element 10 essentially corresponds to the internal diameter of the channel. As a result of such a configuration in the channel, the annular element does not produce any discontinuities which result in turbulence inside the flowing milk. In addition, pressure losses are reduced 15 by such an arrangement. The device having a channel is preferably arranged in such a manner that the channel having a longitudinal axis is inclined with respect to a vertical. As a 20 result, milk can flow out of the channel. This also applies to cleaning liquids or disinfecting liquids which are used to clean the channel. Yet another advantageous configuration of the device 25 according to the invention proposes that the ratio of the width of the annular element to the internal diameter of the at least one annular element be between 0.1 and 25, preferably between 3 and 5. A configuration in which the ratio of the width of the annular element 30 to the internal diameter of the at least one annular element is approximately 4.3 is particularly preferred. A configuration of the device in which the annular element has a width of approximately 5 mm is particularly preferred. This width is particularly 35 preferred in a channel having an internal diameter of 25 mm.

WO 2007/147555 PCT/EP2007/005380 -6 Yet another advantageous configuration of the invention proposes that the at least one pin-shaped element have an essentially circular cross section. A uniform flow around the element is achieved as a result of this 5 shape of the cross section. In addition, the pin-shaped element does not have an adverse effect on the flow of the milk in the channel. Yet another advantageous configuration of the device 10 proposes that the at least one pin-shaped element have a width, preferably a diameter, of between 1 mm and 8 mm. A width or a diameter of between 2.5 and 3.5 mm is particularly preferred. It has been found that a width or a diameter of the pin-shaped element of 3 mm 15 is a particularly preferred configuration. The pin-shaped element is preferably arranged in the channel in an essentially radial manner. It preferably has a length having the diameter of the channel. The 20 pin-shaped element preferably intersects the longitudinal axis of the channel essentially at a right angle. This is not absolutely necessary. The pin-shaped element may intersect the longitudinal axis of the channel at an angle of between 450 and 1350. The 25 preferred configuration of the arrangement of the pin shaped element ensures that the flow of milk is always in contact with the pin-shaped element. Yet another advantageous design of the device proposes 30 that two adjacent elements, in particular an annular element and a pin-shaped element, are arranged at a distance L from one another. The ratio of the distance to the internal diameter of the at least one annular element is between 0.2 and 2.0. A configuration in 35 which the ratio of the distance to the internal diameter of the at least one annular element is between 0.4 and 0.7 is preferred. It is proposed, in WO 2007/147555 PCT/EP2007/005380 -7 particular, that this ratio be approximately 0.55. If the distance between an annular element and the pin shaped element is 12 mm, relatively reliable values for detecting the flow of milk are obtained. 5 The arrangement of the elements is preferably selected in such a manner that the pin-shaped element is arranged downstream of at least one annular element in the direction of flow of the milk. 10 The annular element and the pin-shaped element are preferably connected to an electronic circuit, with the result that the elements form electrodes which are used, with the circuit, to determine the electrical 15 conductivity and/or conductance of the flowing milk. The flow element arranged upstream of the inlet opening of the chamber is preferably formed by the pin-shaped element. This configuration of the device simplifies 20 the device since the pin-shaped element is used, on the one hand, as an electrode and, on the other hand, as a flow element. The flow element casts a flow shadow on the chamber, thus preventing turbulence in flows, in particular in flows of greater than 4 1/min, which 25 influences the measurement operation in the chamber. The measuring unit which is arranged in the chamber preferably comprises two electrodes. The electrodes may be pin-shaped. They preferably have a diameter of 30 approximately 1 mm, in particular 1.5 mm. The electrodes are arranged beside one another in the direction of flow and are preferably at a distance of approximately 7 mm. 35 Yet another advantageous configuration of the invention proposes that the chamber has an outlet opening, preferably an outlet opening whose cross section WO 2007/147555 PCT/EP2007/005380 widens. As a result, the milk which collects in the chamber flows away. The widening is preferably conical, with the result that particles which may be in the flow of milk and which pass into the chamber do not result 5 in the outlet opening becoming blocked. If necessary, the measuring unit may have at least one temperature sensor. This at least one temperature sensor may be used to compensate for the temperature of 10 the conductance measurement. Yet another inventive concept proposes an apparatus for determining a quantity of milk, comprising a device as claimed in one or more of claims 1 to 18, at least one 15 electronic circuit being provided and being connected to the at least two electrically conductive elements by means of signal lines. As a result of the configuration according to the invention of the device and/or apparatus, it is possible to determine the quantity of 20 milk in the flow. Since the flow of milk need not change the direction of flow, disruptive pressure fluctuations do not occur either. Movable parts which are needed to record the measured values are not provided either. The device and apparatus therefore 25 require very little maintenance and are simple to clean and disinfect. Further details and advantages of the invention are explained using the exemplary embodiments illustrated 30 in the drawing without restricting the subject matter of the invention to these specific exemplary embodiments. In the drawing: 35 fig. 1 shows a device in section, and WO 2007/147555 PCT/EP2007/005380 -9 fig. 2 shows the device in conjunction with other parts of a milking system. Fig. 1 shows a device for detecting a flow of milk. The 5 device has an essentially tubular component 1. The component 1 is preferably produced from an electrically non-conductive plastic. The component 1 is preferably produced using the injection-molding method. The component may be produced from polysulfone (PSU), 10 polyamide 12 (PAl2) or polyphenylsulfone (PPSU). Other plastics which are compatible with foodstuffs are likewise suitable. The component 1 has a channel 2. The channel has an 15 inlet 3 and an outlet 4. The cross section of the channel 2 is essentially circular. The reference symbol 5 is used to denote the longitudinal axis of the channel. When the device is installed, the longitudinal axis 5 is inclined with respect to a vertical. As a 20 result, the flow of milk flows at least partially on the wall 9 of the channel 2. Flanges 6, 7 which are suitable and intended for connection to other components of a milking system are 25 provided at the two ends of the channel 2. A flow of milk (not illustrated) enters the channel 2 through the inlet 3 and flows through said channel, the flow of milk flowing out of the channel via the outlet 30 4. It can be seen from the illustration according to fig. 1 that an annular element 8 which is electrically conductive is provided in the channel 2. The annular element 8 has an internal diameter d which essentially corresponds to the internal diameter of the channel 2. 35 The annular element is an integral part of the channel 2. A connection element 10 which is electrically connected to the annular element 8 extends through the WO 2007/147555 PCT/EP2007/005380 - 10 wall 9 of the component 1. In the exemplary embodiment illustrated, the connection element has an internal thread 11 into which a screw can be screwed, with the result that a signal line can be connected and secured 5 to the connection element, for example. An electrically conductive pin-shaped element 12 is provided downstream of the annular element 8 in the direction of flow of a flow of milk. The distance L 10 between the annular element and the pin-shaped element is preferably 12 mm in the exemplary embodiment illustrated. The pin-shaped element 12 penetrates the wall 9. A front end of the pin-shaped element partially extends into the opposite wall 13. It is clear from the 15 illustration in fig. 1 that the pin-shaped element 12 intersects the longitudinal axis 5 of the channel at an angle of approximately 900. The pin-shaped element 12 is arranged essentially parallel to the end faces of the annular element 8. 20 The other end region 14 of the pin-shaped element protrudes from the wall 9. It can be connected to a signal line. 25 The cross section of the pin-shaped element 12 is preferably circular. It has, in particular, a diameter of approximately 3.0 mm. The annular element 8 and the pin-shaped element 12 are connected to an electrical circuit (not illustrated). The conductivity of the 30 flowing milk is measured using the electrically conductive elements 8, 12. A chamber 15 is arranged under the pin-shaped element 12. The chamber 15 is provided in the region of the 35 wall 9. The chamber 15 has an inlet opening 16 through which some of the flowing milk can flow into the chamber 15. An outlet opening 17 is provided at the WO 2007/147555 PCT/EP2007/005380 - 11 lowest point in the chamber 15. The outlet opening 17 preferably has a diameter of approximately 1.4 mm. The outlet opening is preferably designed in such a manner that its cross section widens outward. This widening 5 from inside to outside ensures that the particles which are possibly in the milk cannot collect in the outlet opening. Larger dirt particles are flushed out of the chamber 15 by the flow of the milk. 10 A measuring unit 18 is arranged inside the chamber 15. The measuring unit 18 is formed by two electrodes 19 which are arranged beside one another. The electrodes 19 are essentially pin-shaped. They preferably have a diameter of approximately 1.5 mm. The arrangement of 15 the electrodes 19 is selected in such a manner that they are at a distance of approximately 7 mm from one another. The electrodes 19 are connected to a circuit (not illustrated) by means of a connection option (not illustrated). The electrodes 19 project approximately 3 20 to 4 mm into the chamber 15. The conductance of the milk is measured in the chamber 15 using the measuring unit 18. The pin-shaped element 12 forms a flow element which is 25 arranged upstream of the inlet opening 16 of the chamber 15 in such a manner that formation of turbulence in the chamber 15 is at least reduced, if not even prevented. As a result of the fact that turbulence is avoided in the chamber 15, the 30 conductance of the milk is measured inside the chamber 15 with a high degree of reliability. Measurement errors which result from the milk, which flows into the chamber 15, being mixed with air, thus changing the conductance of the mixture, could be virtually 35 eliminated by the configuration.

WO 2007/147555 PCT/EP2007/005380 - 12 The design according to the invention of the device for detecting a flow of milk provides measured values which have a high degree of accuracy. The configuration of the device is selected in such a manner that the 5 channel and the chamber can be well cleaned and emptied. The chamber 15 is emptied automatically. The device can provide a control device with a signal both at the start and at the end of a milking operation, with the result that pulsation is switched off, for 10 example as a milking operation ends, and a signal for removing the milking cluster is generated. The device can also be used as a so-called kick-off sensor. If there is a sudden influx of air during a milking operation, the conductivity measured between the 15 electrodes 8 and 12 also suddenly decreases. Depending on the configuration of the circuit (not illustrated) and the time of kick-off in the milking operation, signaling can then be effected or the milking cluster can be removed. 20 The profile of the conductance of the milk can be determined using the conductance measurement which is carried out in the chamber 15. This profile allows conclusions to be drawn regarding the state of health 25 of the milk-yielding animal. Fig. 2 shows the arrangement of the device in conjunction with other components of a milking system. The same components of the device are provided with the 30 same reference symbols. The component 1 can be seen in fig. 2. It can be seen that the component 1 has a connection chamber 20 which accommodates the connections for the electrically conductive elements and the electrodes. The component 1 is connected to a 35 milk tube 21. The milk tube 21 has a shut-off means 22 which can be pneumatically actuated. Such a shut-off WO 2007/147555 PCT/EP2007/005380 - 13 means is disclosed, for example, by the utility model 295 03 450.5. The milk tube 21 has a flange which is designed in a 5 manner corresponding to the flange 6. The flanges are connected to one another by means of two connecting elements 23. The connecting elements 23 are in the form of half-shells. They have internal grooves in which the flanges engage. The connecting elements 23 are 10 connected in a frictionally locking manner by means of a spring-elastic element 24. The flange of the component 1 can be connected to another part of the milking system in a corresponding manner. The component 1 has a flange 6. The flange 6 has a projection 25 in 15 the form of a lug. The projection engages in a correspondingly designed depression in a flange of the shut-off means 22. This measure results, on the one hand, in a defined installation position and, on the other hand, in a rotationally secured connection 20 between the component 1 and the shut-off means 22. It can be seen from the illustration in fig. 2 that the connecting elements 23 at least reduce contamination of the connecting points as a result of deflectors 26 25 which are correspondingly formed on the component 1. As a result of the configuration according to the invention of the device for detecting a flow of milk, conductivity can be reliably measured in the range of 30 1 mS/cm to 12 mS/cm. In addition, the device according to the invention opens up the determination of quantities of milk in the milk volumetric flow range of 0.0 to 9.0 1/min.

WO 2007/147555 PCT/EP2007/005380 - 14 List of reference symbols 1 Component 2 Channel 3 Inlet 4 Outlet 5 Longitudinal axis 6 Flange 7 Flange 8 Annular element 9 Wall 10 Connection element 11 Thread 12 Pin-shaped element 13 Wall 14 End region 15 Chamber 16 Inlet opening 17 Outlet opening 18 Measuring unit 19 Electrode 20 Connection chamber 21 Milk tube 22 Shut-off means 23 Connecting element 24 Spring-elastic element 25 Projection 26 Deflector

Claims

1. A device for detecting a flow of milk, having a channel, which has an inlet and an outlet, and having at least two electrically conductive elements which are 5 arranged at a distance from one another in the channel, wherein at least one element is essentially annular and at least one element is essentially pin-shaped, and wherein the channel has at least one chamber having a measuring unit for measuring the conductance of the milk, the chamber having an inlet opening upstream of which a flow element is arranged. 1o

2. The device as claimed in claim 1, wherein the channel has at least one section between two adjacent electrically conductive elements which is composed of an electrically non-conductive material.

3. The device as claimed in claim 2, wherein the channel is formed from at least one electrically non-conductive polymer. is

4. The device as claimed in any one of the preceding claims, wherein the channel has a longitudinal axis which is inclined with respect to a vertical.

5. The device as claimed in any one of the preceding claims, wherein the at least one annular element has an internal cross section which essentially corresponds to an internal cross section of the channel. 20

6. The device as claimed in claim 5, wherein the at least one annular element has an internal diameter which approximately corresponds to the internal diameter of the channel.

7. The device as claimed in any one of the preceding claims, wherein the at least one annular element is an integral part of the channel. 25

8. The device as claimed in any one of the preceding claims, wherein the at least one annular element has a width, the ratio of the width of the annular element to the internal diameter of the at least one annular element being between 0.1 and 25, preferably between 3 and 5, in particular 4.3.

9. The device as claimed in any one of the preceding claims, wherein the 30 at least one pin-shaped element has an essentially circular cross section.

10. The device as claimed in claim 9, wherein the at least one pin-shaped element has a width, preferably a diameter, of between 1 mm and 8 mm, preferably between 2.5 mm and 3.5 mm, in particular a diameter of 3.2 mm. 16

11. The device as claimed in any one of the preceding claims, wherein the at least one pin-shaped element intersects the longitudinal axis of the channel at an angle of between 450 to 1350, preferably essentially at an angle of 90*.

12. The device as claimed in any one of the preceding claims, wherein two s adjacent electrically conductive elements are arranged at a distance from one another, the ratio of the distance to the internal diameter of the at least one annular element being between 0.2 and 2.0, preferably between 0.4 and 0.7, in particular 0.55.

13. The device as claimed in any one of the preceding claims, wherein the pin-shaped element is arranged downstream of at least one annular element in the 10 direction of flow of the milk.

14. The device as claimed in any one of the preceding claims, wherein the at least one chamber is arranged downstream of the electrically conductive elements in the direction of flow of the milk.

15. The device as claimed in any one of the preceding claims, wherein the is flow element is at least partially formed by the pin-shaped element.

16. The device as claimed in any one of the preceding claims, wherein the measuring unit has at least two electrodes.

17. The device as claimed in any one of the preceding claims, wherein the chamber has an outlet opening, preferably an outlet opening whose cross section widens. 20

18. The device as claimed in any one of the preceding claims, wherein the measuring unit has at least one temperature sensor.

19. An apparatus for determining a quantity of milk, comprising at least one device as claimed in any one of claims I to 18 and at least one electronic circuit which is connected to the at least two electrically conductive elements by means of signal lines. 25

20. A device for detecting a flow of milk substantially as hereinbefore described with reference to the accompanying drawings. Dated 25 January 2011 GEA WestfaliaSurge GmbH 30 Patent Attorneys for the Applicant/Nominated Person SPRUSON & FERGUSON