WO2013122454A1

WO2013122454A1 - Milking device and method for cleaning the milking device

Info

Publication number: WO2013122454A1
Application number: PCT/NL2013/050050
Authority: WO
Inventors: Michiel Adriaan Van Dorp
Original assignee: Lely Patent N.V.
Priority date: 2012-02-15
Filing date: 2013-01-30
Publication date: 2013-08-22
Also published as: NL2008293C2

Abstract

A milking device with a sampling device with a block-and-bleed valve assembly, and a method for cleaning thereof. The valve assembly comprises two three-way valves (8, 12), connected by a connector (11) and each having a bleed (10, 14). The method provides cleaning of the valves and the bleeds by pressing pressurised cleaning fluid to the sampling device side of the valve assembly, wherein the sampling device itself closes off the fluid passage, using a predetermined accumulator function. After switching the valve assembly to release the accumulated fluid, the latter can also clean the bleed that was closed during accumulating the fluid. Thus a simple and reliable valve assembly, and method of cleaning same, is obtained.

Description

Milking device and method for cleaning the milking device

The present invention relates to a milking device with a milk line, and more in particular to such a milking device with a cleaning arrangement for arranging at least a part thereof.

In practice, it is of the utmost importance to clean all parts that come into contact with milk for human consumption. It is also important to obtain desired information about such milk, such as information relating to milk quality and possible infections of the dairy animal producing the milk. Thereto, the milking device is often provided with a milk sampling device connected to the milk line. It may be desirable, or even required, to be able to disconnect the milk sampling device reliably from the milk line, to prevent milk from a previous sample from reaching the milk of a subsequent dairy animal. For if a sample shows that the milk is not fit for human consumption, not even a sample thereof should come into contact with a subsequent amount of milk that is fit for human consumption. Even more so, if the milk sampling device uses reagents or other fluids that are not to end up in the milk, such a reliable disconnection is very desirable. In the prior art, there are known closing devices that are able to close off the connection between milk sampling device and milk line.

There is then a need to reliably clean the closing device, because it may be possible that milk remains behind on or behind parts of the closing device. For example, WO2010/094577 discloses separable fluid systems with bypass valve system, as well as cleaning thereof, while US 5469880 discloses a block-and-bleed valve assembly with a cleaning solution supply.

The known systems are sometimes rather complex, as may be the procedure for cleaning same.

There is therefore a need to provide a milking system with a closing device between the milk line and a milk sampling device, that is easily cleaned, as well as a method for easily cleaning same, or at least a useful alternative to the public.

The invention achieves this object at least in part with a milking device according to claim 1 , in particular a milking device with a milk line, and with a pump and a milk sampling device that are operatively connected to the milk line, as well as with a cleaning device for cleaning at least a part of the milk line and a part of the milk sampling device, wherein the milk sampling device comprises a analysis device, a sample line to the analysis device, which sample line is connected to the milk line, and a closing device that is provided in the sample line between the closing device and the analysis device, wherein the milk sampling device has, at least from the closing device, and in particular from and including the closing device, a predetermined minimum accumulator capacity for fluid, in particular at a predetermined cleaning pressure, more in particular at a pressure between 2 and 5 bar, yet more in particular at 3 bar, and wherein the closing device comprises a housing with: a sample supply, a sample discharge, a connector between the sample supply and the sample discharge, a first bleed, a second bleed, a first controllable block-and-bleed three-way valve between the sample supply, the connector and the first bleed, having a first state in which the sample supply is closed off and the connector and the first bleed are in fluid connection, and a second state in which the sample supply and the connector are in fluid connection and the first bleed is closed off, as well as a second controllable block-and-bleed three-way valve between the sample discharge, the connector and the second bleed, and having a third state in which the sample discharge is closed off and the connector and the second bleed are in fluid connection, and a fourth state in which the sample discharge and the connector are in fluid connection and the second bleed is closed off, wherein the milking device comprises a control unit arranged to control at least one of the first and second controllable three-way valves, wherein the control unit is arranged to carry out the following successive steps: putting the first three-way valve in the first state and putting the second three-way valve in the third state, putting the first three-way valve in the second state, putting the second three-way valve in the fourth state after a first predetermined time period, putting the first three-way valve in the first state after a second predetermined time period.

The present invention uses the insight that providing an accumulation function to a part of the milk sampling device that is in fact in or downstream from the closing device may suffice for cleaning a valve that either closes off the flow of fresh cleaning fluid into the closing device, or closes off its own bleed, at least in the configuration of the present invention. Thus, there would otherwise be no fresh cleaning fluid available for cleaning at least the bleed of the valve that closes off the flow of fresh cleaning fluid. Now, according to the invention, such fluid is available from the accumulated fluid, the accumulation being caused by the pressure with which the cleaning fluid is, and must be, provided.

In practice, the amount of cleaning fluid for cleaning need not be large. Therefore, the predetermined minimum capacity accumulation need also not be large, but may be for example between 0.1 and 5 cm³, in particular from 1/2 to 2 cm³.

Particular embodiments are the subject of the dependent claims. In particular, however, the milk sampling device comprises a sample valve that is closable by the control unit, or a pump that in at least one state closes off the sample line, in particular a peristaltic pump. This ensures that there is sufficient counterpressure in the milk sampling device for the accumulation of (cleaning) fluid. Herein, the sample valve may be a valve that is provided close to the milk analysis device, or at least such that the sample line by itself has a sufficient accumulation capacity. Alternatively or additionally, the closing off is provided by the sample pump itself, the sample pump being a pump that closes off the sample line in at least one state. In particular this pump (sample pump) is a peristaltic pump, or roller pump, that is often used in clean environments. Such a type of pump offers an advantage that there are no moving parts in the line, and the milk sample only contacts the inside of the tubing of the sample pump. Thus there is no concern for valves, rings or seals etc. that might become soiled or give off contamination into the sample. In other words, cross-contamination with exposed pump components apart from the tubing cannot occur. Furthermore, it is also a useful pump for accurately displacing small quantities. Nevertheless, other types of sample pump are not to be excluded, such as piston pumps or diaphragm pumps.

In embodiments, the first and/or the second three-way valve comprise a moveable valve body, wherein the closing device comprises a first actuator and second actuator that are arranged for switching the first three-way valve between the first and the second state, and for switching the second three-way valve between the third and the fourth state, respectively, under the control of the control unit. These actuators are provided for carrying out the required steps of closing the sample supply and/or sample discharge, or the respective bleeds. The actuators may be selected according to any further requirement, if any.

In particular, at least one of the first and the second three-way valve comprises a magnetic or magnetisable moveable valve body, wherein the corresponding first and/or the second actuator, respectively, comprises a magnet device that is controllable by the control unit, for the first and/or the second three way valve, respectively. Herein, the respective valve body is made of, or at least comprises, a magnetic material or a material that is magnetisable under the influence of a magnetic field. Such magnetic valves have the advantage of not requiring any connection to the outside world, since the valve body is controllable by a magnetic field that can be generated by the magnet device. The latter preferably comprises an electromagnet.

Alternatively and/or additionally, at least one of the first and the second valve body comprise an extension that extends to within the first or second bleed, wherein the first and/or second actuator, respectively, is arranged for operating or engaging said extension. In this embodiment, the (internal) valve body has an extension, by which some external actuator(s) may control the position of the valve body, and thus the state of the valve. This allows a direct and reliable control of the valve, although it may require measures to seal off the passage of the extension through the bleed.

In embodiments, the said accumulator capacity for fluid is provided in at least a part of the sample line. In particular, said accumulator capacity is provided in a part of the sample line between the closing device and the milk analysis device. This is a very simple way to provide the accumulator capacity while not requiring special measures or features for the milk analysis device.

In particular, the sample line, or at least the relevant part thereof, and/or the connector comprises, or in particular consists of, a material with a predetermined minimum flexibility, in particular silicone material. Herein the natural flexibility of the chosen material should provide the minimum accumulator capacity at the desired pressure level, such as 1 cm³ at three bar pressure. Of course, the accumulator capacity depends on the length of the sample line and/or the connector, at least of the part that provides the accumulator capacity.

The cleaning device in the milking device according to the present invention may comprise a cleaning fluid inlet. This may suffice if the pump is used for pumping and/or pressurizing the cleaning fluid. The pump may be the milk pump or a separate, dedicated cleaning fluid pump. This is a very simple set-up, with it even being possible to use one or more teat cups as the cleaning fluid inlet, the latter being operatively connected or connectable via a valve, to the milk line. The cleaning device may further comprise a cleaning fluid storage connected to the cleaning fluid inlet. This makes it possible to automate the cleaning procedure, as the presence of an operator for providing cleaning fluid to the inlet is no longer required. It is also possible to connect an outlet of the milk line to the cleaning fluid inlet, thus effectively providing a so-called (re)circulation cleaning.

In particular embodiments, the milking device comprises a plurality of analysis devices, each connected by means of a closing device to a respective sample line. Then, each respective sample line and closing device may be cleaned in substantially the same way and with the same means as disclosed herein for the single closing device case. However, it is also possible that the respective first controllable block-and-bleed three-way valves are combined into a single four-way valve, connected to the respective connectors, which are in turn each connected to a respective second controllable block-and-bleed three-way valve. Then, the closing device may be closed by performing the mentioned steps consecutively for each combination of connector and second three-way valve together with the appropriate setting for the four-way valve. Other configurations and cleaning orders are not excluded, such as a single sample supply and a connector that splits into two sample discharges, via a splitter connector, each connected to a three-way valve, or a single connector connected between the sample supply and a four-way valve, the latter in turn connected to two sample discharges, and so on.

In embodiments, the milk sampling device and/or the connector comprise an accumulator having at least the predetermined minimum accumulator capacity. Herein, the accumulator can be a dedicated accumulator, that is operatively coupled with the closing device, at least during the relevant steps in operating the closing device. The accumulator may for example comprise a storage container that is operably connected to the sample line or connector, and has an amount of gas that is closed off by a flexible membrane between the gas and the sample line or connector. Such an accumulator is well-known in the art, and details need not be provided here.

The invention also relates to a method for cleaning a device according to the invention, the method comprising: supplying, via the milk line towards the closing device, a fluid under pressure, in particular a cleaning fluid and in particular under a pressure of between 2 and 5 bar, more a particular 3 bar, putting the first three-way valve in the first state and putting the second three-way valve in the third state, subsequently putting the first three-way valve in the second state, subsequently putting the second three-way valve in the fourth state after at least a first predetermined time period, subsequently putting the first three-way valve in the first state after at least a second predetermined time period. This method provides a simple but reliable way to clean the milking device, in particular the closing device thereof, at least the sample supply, sample discharge and both bleeds. Of course, after this cleaning, the three-way valves may be put in any combination of states suitable for a subsequent purpose.

In particular embodiments, the first and/or the second predetermined time period is between 0.5 and 2 seconds. Such time periods ensure a sufficient cleaning of the relevant bleed. Of course, other time periods may be selected.

The invention will now be elucidated by means of a number of non-limiting embodiments and drawings, in which:

Figure 1 diagrammatically depicts a milking device 1 according to the invention;

Figure 2 diagrammatically shows two different three-way valves in a cross- sectional view; and

Figures 3a-3c diagrammatically show various steps of the method according to the invention.

Figure 1 diagrammatically depicts a milking device 1 according to the invention. The device comprises a milking means 2, a milk line 3 and a milk pump 4, as well as a closing device, generally designated 5, via a sample line (first part) 6. The closing device 5 comprises a housing 7 and a first three-way valve 8 between a sample supply 9 and a first bleed 10, as well as a connector 1 1 to a second three-way valve 12 between a sample discharge 13 and a second bleed 14.

The sample discharge 13 leads via a second part of the sample line 15 to an analysis device 16, with a sample pump 17. Reference numeral 18 designates an accumulator, while a sample valve has been indicated by 19.

An optional milk line valve 20 is connected to a milk discharge 21 , and, via optional recirculation valve 22 to an optional recirculation line 23.

The milking means 2 have been indicated very diagrammatically and may comprise robotic milking means and/or conventional milking means. The milk line 3 runs from the milking means 2 to the milk discharge 21 , that may be a milk tank, a connection to a milk feeder, a sewer, and so an. Milk line valve 20 is optional, and may comprise a multiway valve for directing a flow of milk to e.g. any of the mentioned destinations. Optionally, such a milk valve 20 may comprise a recirculation valve 22 connected to a recirculation line 23 leading back to the milking means 2. Such embodiment relates to a milking device with recirculation cleaning. However it is also possible to do without such a recirculation line, and have one-way cleaning. Not separately depicted is a cleaning fluid inlet, such as for example teat cups of the milking means 2. An optional cleaning fluid storage is neither shown.

The closing device 5 is connected to milk line 3 via a sample line 6, in particular the first part thereof. The closing device serves to close off the connection between the milk sample device from the milk line 3. Note that the milk sampling device may be said to comprise the closing device 5, the analysis device 16 and all parts connecting the two. Alternatively, the milk sampling device proper may be said to comprise only the analysis device 16. In all cases, such a closing device is relevant to protect the milk that runs through the milk line 3 from any reagent that might be used in the analysis device 16. Regulations demand that such a closing off, or disconnection, is leakproof. Thereto, often, use is made of a block-and-bleed valve. In the present invention, this is embodied as two three-way valves 10 and 12, in combination with a first bleed 10 and a second bleed 14, and connected by a connector 1 1.

Various parts of the milking device 1 are controlled by means of control unit 30. Such parts may comprise the milk pump 4, valves of the closing device 5 as well as the (optional) sample valve 19. It is explicitly noted that, although designated a milk pump, the pump designated with reference numeral 4 may also be a separate pump for pumping and/or pressurizing cleaning fluid for cleaning the milk line 3 as well as the sample line 6 and the closing device 5. In other words, the milking means 2 may comprise a container for cleaning fluid, while pump 4 may be designated a cleaning fluid pump. In this case, too, the closing device 5 serves to close off any connection between the milk line 3 and the analysis device 16.

The first three-way valve 8 may connect the connector 11 , which in turn connects to the first part of the sample line 6, to either the sample supply 9 or the first bleed 10. Similarly, the second three-way valve 12 may connect the connector 1 1 , which in turn connects to the second part of the sample line 15, to either the sample discharge 13 or the second bleed 14. In use, when cleaning the milking device 1 , the following steps can be taken. First, the first three-way valve 8 is operated to be in a first state, in which the sample supply 9 is blocked, and the connector 1 1 and the first bleed 10 are connected. Furthermore, the second three-way valve 12 can in principle be operated to be in any state, but will preferably be in a third state in which the sample discharge 13 is blocked, and the connector 1 1 and the second bleed 14 are connected. The analysis device 16 is thus fully separated from the milk line 3. Any fluid that still enters the closing device via sample line parts can leak away via the first and/or second bleed. The milk line 3 can then be cleaned by passing cleaning fluid theretrough, e.g. by means of pumping with the milk pump 4. Cleaning fluid may be discharged to a sewer or the like, via valve 20, or may be recirculated via optional valve 22 and recirculation line 23.

If it is desired that the closing device 5 is cleaned, as a first step the three- way valve 8 will be put in a second state, in which the first bleed 10 is blocked, and the sample supply 9 is connected to the connector 1 1. The second three-way valve 12 is still in the third state. Now, cleaning fluid will flow from the milk line 3 via the sample line 6, the sample supply 9, the first three way valve 8, the connector 1 1 , the second three way valve 12, and the second bleed 14. Thus, all internal parts of the closing device 5 will be cleaned, except for the first bleed 10 and that part of the second three way valve 12 that connects to the sample discharge 13.

In a subsequent step, the second three-way valve 12 is put in a fourth state, in which the second bleed 14 is closed off, and the connector 1 1 and the sample discharge 13 are connected. Now, cleaning fluid will flow through the sample supply 9, the connector 1 1 and sample discharge 13 at least partly into the second part 15 of the sample line. Note that at least during a last part of this step, the flow path for cleaning fluid to the analysis device 16 is blocked. This may be ensured by closing off sample valve 19, or by having the sample pump 17 in a closing-off state. For example, the sample pump 17 is a peristaltic pump, which always effectively blocks flow-through of fluid. The nett result of this closing off will be that, under the pressure of the cleaning fluid, the accumulator 18 will collect a certain, predefined amount of cleaning fluid. This accumulator 18 may be a dedicated accumulator or may use any natural flexibility of the second part of the sample line 15. In order not to damage parts, the source of pressure for the cleaning fluid may be turned off during or before this step, as long as it is ensured that the predetermined amount of cleaning fluid is collected.

In a subsequent step, the first three-way valve 8 is put into the first state, in which the sample supply 9 is closed off, and the connector 1 1 is connected to the first bleed 10. In this situation, there is a connection from the accumulator 18 via the two tree-way valves 8 and 12 to the first bleed 10. Thus, collected cleaning fluid will flow via this path and clean the first bleed 10. All steps may be performed during a predetermined minimum time. For example, the second step, for cleaning the second bleed 14, the third step for accumulating cleaning fluid, and the fourth step, for cleaning the first bleed 10, may each last e.g. a second, although that period of time depends on the dimensions of the system, the pressure used, the selected accumulator capacity and so on.

The predetermined minimum amount of fluid that is collected or accumulated in the accumulator 18 need not be very large, because effectively, only a small amount of fluid suffices for cleaning the bleed 10. Therefore, having a flexible second part of the sample line 15 may suffice in practice. A useful amount may be between 0.1 and 1 cm³ , although any other predetermined amount is possible as well, depending on for example the dimensions of the closing device 5 and its parts. In all the above steps, the various operations may be under the control of the control unit 30, although there may be separate control units, that communicate with the requisite other parts and/or control units.

Figure 2 diagrammatically shows two different three-way valves in a cross- sectional view. Herein, 24 designates a first valve body, and 25 and 26 a first magnet and a second magnet, respectively. A second valve body 27 has an extension 28. As in all of the drawings, similar parts are denoted with the same reference numerals.

In the left three-way valve, the first valve body 24 is made of a magnetic material or a magnetisable material. The magnets 24 and 25 are preferably electromagnets, although in particular the first magnet 25 may also be a permanent magnet in case the first valve body is made of a magnetic material, as in the case of failure of the second magnet 26, being an electromagnet, the permanent closing off of the sample supply 9 may be ensured as a safety measure. In other cases the position of the first valve body 24 can be controlled by controlling the first and/or second magnet 25 and 26. For example, if the first electromagnet is energized and the second magnet 26 is not, the first valve body 24 will be moved upwards and block sample supply 9. This corresponds to the first state mentioned in figure 1. Conversely, when the second magnet 26 is energized and the first magnet 25 is not, the valve body 24 will be moved downwardly, closing off the first bleed 10. This corresponds to the second state.

In the right part of figure 2, there is shown a second valve body 27 with an extension 28 that extends through the second bleed 14 to outside the housing 7. This allows e.g. mechanical control over the position of the second valve body 27. For example, when the second valve body 27 is moved upwardly, the sample discharge 13 may be blocked. This corresponds to the third state as mentioned for figure 1 . And when the second valve body 27 is moved downwardly, the second bleed 14 may be blocked, corresponding to the fourth state.

Of course, other set-ups for the various three-way valves are possible, such as those that use a spring, or pneumatic or hydraulic actuators. Such details are known to the skilled person.

Figure 3a shows a first situation, in which the first threeway valve 8 is in a the second state and the second three way valve 12 is in the third state. This allows a flow of cleaning fluid, as indicated by the arrows, from the sample supply 9 via the connector 1 1 to the second bleed 14. Note the relatively low level of fluid in the accumulator 18.

In a subsequent step, the second three-way valve 12 is put into the fourth state, effectively redirecting the cleaning fluid flow towards the second part 15 of the sample line and accumulator 18, which now at least partly fills with fluid. This is indicated with a relatively high level line.

In a subsequent step the first three-way valve 8 is put into the first state, thereby closing off sample supply 9, and allowing fluid to flow from the accumulator 18, via the second part 15 of the sample line and the connector 1 1 , to the first bleed 10. The level in the accumulator 18 is now relatively low again. Now all parts of closing device in the housing 7 have been cleaned. The above described embodiments are in no way deemed limiting. Rather, the scope of the invention is determined by the appended claims.

Claims

1. A milking device with a milk line, and with a pump and a milk sampling device that are operatively connected to the milk line, as well as with a cleaning device for cleaning at least a part of the milk line and a part of the milk sampling device, wherein the milk sampling device comprises a analysis device, a sample line to the analysis device, which sample line is connected to the milk line, and a closing device that is provided in the sample line between the closing device and the analysis device, wherein the milk sampling device has, at least from the closing device, and in particular from and including the closing device, a predetermined minimum accumulator capacity for fluid, in particular at a predetermined cleaning pressure, more in particular at a pressure between 2 and 5 bar, yet more in particular at 3 bar,

and wherein the closing device comprises a housing with:

- a sample supply,

- a sample discharge,

- a connector between the sample supply and the sample discharge,

- a first bleed,

- a second bleed,

- a first controllable block-and-bleed three-way valve between the sample supply, the connector and the first bleed, having a first state in which the sample supply is closed off and the connector and the first bleed are in fluid connection, and a second state in which the sample supply and the connector are in fluid connection and the first bleed is closed off, as well as

- a second controllable block-and-bleed three-way valve between the sample discharge, the connector and the second bleed, and having a third state in which the sample discharge is closed off and the connector and the second bleed are in fluid connection, and a fourth state in which the sample discharge and the connector are in fluid connection and the second bleed is closed off,

wherein the milking device comprises a control unit arranged to control at least one of the first and second controllable three-way valves,

wherein the control unit is arranged to carry out the following successive steps: - putting the first three-way valve in the first state and putting the second three-way valve in the third state,

- putting the first three-way valve in the second state,

- putting the second three-way valve in the fourth state after a first 5 predetermined time period,

- putting the first three-way valve in the first state after a second predetermined time period.

2. The milking device according to claim 1 , wherein the milk sampling device comprises a sample valve that is closable by the control unit, or a pump that in at least o one state closes off the sample line, in particular a peristaltic pump.

3. The milking device according to claim 1 or 2, wherein the first and/or the second three-way valve comprise a moveable valve body, wherein the closing device comprises a first actuator and second actuator that are arranged for switching the first three-way valve between the first and the second state, and for switching the second5 three-way valve between the third and the fourth state, respectively, under the control of the control unit.

4. The milking device according to claim 3, wherein at least one of the first and the second three-way valve comprises a magnetic or magnetisable moveable valve body, wherein the corresponding first and/or the second actuator, respectively,0 comprises a magnet device that is controllable by the control unit, for the first and/or the second three way valve, respectively. Herein, the respective valve body is made of, or at least comprises, a magnetic material or a material that is magnetisable under the influence of a magnetic field.

5. The milking device according to claim 3, wherein at least one of the first5 and the second valve body comprise an extension that extends to within the first or second bleed, wherein the first and/or second actuator, respectively, is arranged for operating or engaging said extension.

6. The milking device according to any one of the preceding claims, the said accumulator capacity for fluid is provided in at least a part of the sample line.

0 7. The milking device according to claim 6, wherein the sample line and/or the connector comprises, or in particular consists of, a material with a predetermined minimum flexibility, in particular silicone material.

8. The milking device according to claim 1 or 2, wherein the milk sampling device and/or the connector comprise an accumulator having at least the predetermined minimum accumulator capacity.

9. The milking device according to any one of the preceding claims, wherein the predetermined minimum accumulator capacity is between 0.1 and 5 cm³, in particular between tussen 1/2 and 2 cm³.

10. A method for cleaning a device according to any one of the preceding claims, the method comprising:

- supplying, via the milk line towards the closing device, a fluid under pressure, in particular a cleaning fluid and in particular under a pressure of between 2 and 5 bar, more a particular 3 bar,

- putting the first three-way valve in the first state and putting the second three-way valve in the third state,

- subsequently putting the first three-way valve in the second state, - subsequently putting the second three-way valve in the fourth state after at least a first predetermined time period,

- subsequently putting the first three-way valve in the first state after at least a second predetermined time period.

1 1 . The method according to claim 10, wherein the first and/or the second predetermined time period is between 0.5 and 2 second.