IES85007Y1 - A method and apparatus for minimising power requirement of a vacuum system of a vacuum operated milking system. - Google Patents

Abstract

ABSTRACT The present invention relates to a method and apparatus for minimising the power requirement of a vacuum system of a vacuum operated milking system.

Description

A method and apparatus for minimising power requirement of a vacuum system of a vacuum operated milking system The present invention relates to a method and apparatus for minimising the power requirement of a vacuum system of a vacuum operated milking system.

Such vacuum operated milking systems for milking animals such as cows are well known, and have been known and used for many years, and typically are installed in a milking parlour, in which bail apparatus is provided to form a plurality of cubicles arranged side by side relative to each other for accommodating the animals during milking. Such vacuum operated milking systems require a main milk pipeline to which a plurality of milking clusters are coupled for engaging the teats of animals to be milked. The main milk pipeline typically extends overhead above the bail apparatus, and the milking clusters are Teed off from the main milk pipeline at spaced apart intervals corresponding to the cubicles. A continuous vacuum is applied to the main milk pipeline for drawing milk from the animal’s teats through the milking clusters, and in turn through the main milk pipeline to a milk receiver through which the continuous vacuum is applied to the main milk pipeline by a vacuum system. A pulsator valve is coupled to the vacuum system for producing a pulsating vacuum, which is applied to the milking clusters for pulsating teat liners, which are located in cups of the milking cluster during milking in order to periodically reduce the pressure on the animal's teats, thus allowing blood to circulate in the teats during milking. Such milking systems also include a washing system for facilitating washing of the main milk pipeline as well as the milking clusters, and connecting pipes which connect the milking clusters to the main milk pipeline. Vacuum operated milking systems with such washing systems will also be well known to those skilled in the art. Such a milking system and washing system is disclosed in Irish Patent Specification No. 81697 and corresponding British Patent Specification No. 2,316,290. In the milking system disclosed in these two Patent specifications, apparatus is provided for accumulating washing and rinsing water so that the washing and rinsing water can be sequentially urged through the main milk pipeline and the milking clusters with full flow characteristics.

While the vacuum operated milking system disclosed in these two specifications is perfectly adequate for milking animals and subsequent washing and rinsing of the system, nonetheless, the power requirement for the vacuum system is relatively high, and in general, is particularly high during washing and rinsing cycles. This is undesirable, since the components of the vacuum system, namely, the one or more vacuum pumps which may be required to provide an adequate vacuum, and the motors, which typically are electrically powered to drive the vacuum pump or pumps must be selected to cope with the maximum vacuum demand on the vacuum system by the milking system.

There is therefore a need for a method and apparatus for minimising the power requirement of the vacuum system of such a milking system, and there is also a need for a method and apparatus for minimising the power requirement of a vacuum system of other types of milking systems.

The present invention is directed towards providing such a method and apparatus.

According to the invention there is provided a method for minimising the power requirement of a vacuum system of a vacuum operated milking system, the method comprising isolating a pulsating vacuum generator of the milking system from the vacuum system during at least a portion of a cleaning cycle of the milking system at least while the vacuum demand on the vacuum system is greatest.

In one embodiment of the invention the pulsating vacuum generator is isolated from the vacuum system while the milking system is being operated for urging a cleaning liquid to flow through at least a portion of the milking system with full flow characteristics.

Preferably, the pulsating vacuum generator is isolated from the vacuum system prior to the milking system being operated for urging the cleaning liquid to flow through at least the portion of the milking system with the full flow characteristics, and advantageously, the pulsating vacuum generator is maintained isolated from the vacuum system for a time period after the milking system has ceased to be operated for urging the cleaning liquid to flow through the at least portion of the milking system with the full flow characteristics, and ideally, the pulsating vacuum generator is maintained isolated from the vacuum system for a short time after the milking system has been operated for urging the cleaning liquid to flow through the at least portion of the milking system with the full flow characteristics.

In one embodiment of the invention the pulsating vacuum generator is isolated from the vacuum system for a time period of at least one second prior to commencement of the operation of the milking system for urging the cleaning liquid to flow through the at least a portion of the milking system with the full flow characteristics.

Preferably, the pulsating vacuum generator is isolated from the vacuum system for a time period typically of less than ten seconds prior to commencement of the operation of the milking system for urging the cleaning liquid to flow through the at least a portion of the milking system with the full flow characteristics, although the pulsating vacuum generator may be isolated from the vacuum system for a time period greater or less than ten seconds prior to commencement of the operation of the milking system for urging the cleaning liquid to flow through the at least a portion of the milking system with the full flow characteristics.

In one embodiment of the invention the pulsating vacuum generator is isolated from the vacuum system for a time period of at least one second after the milking system has ceased to be operated for urging the cleaning liquid to flow through the at least a portion of the milking system with the full flow characteristics.

Preferably, the pulsating vacuum generator is isolated from the vacuum system for a time period typically of less than ten seconds after the milking system has ceased to be operated for urging the cleaning liquid to flow through the at least a portion of the milking system with the full flow characteristics. although the pulsating vacuum generator is isolated from the vacuum system for a time period greater than or less than ten seconds after the milking system has ceased to be operated for urging the cleaning liquid to flow through the at least a portion of the milking system with the full flow characteristics.

In another embodiment of the invention the cleaning liquid is a washing liquid, and preferably, an aqueous based washing liquid, and ideally, comprises a mixture of water and a cleaning composition, which preferably, is a detergent, and advantageously, is in liquid form.

In another embodiment of the invention the cleaning liquid is a rinsing liquid, and preferably, is clean water.

In a further embodiment of the invention the washing composition comprises a disinfectant.

The invention also provides a milking system comprising a main milk pipeline and a plurality of milking clusters connected to the pipeline, a vacuum system for applying a continuous vacuum to the main milk pipeline, and a pulsating vacuum generator coupled to the vacuum system for providing a pulsating vacuum for applying to the milking clusters, a washing means being provided for urging a cleaning liquid through at least a portion of the milking system, and an isolating means for selectively isolating the pulsating vacuum generator from the vacuum system.

Preferably, the isolating means is responsive to the presence of an operating signal for isolating the pulsating vacuum generator from the vacuum system, and is responsive to the absence of an operating signal for reconnecting the pulsating vacuum generator to the vacuum system.

In one embodiment of the invention the operating signal is applied to the isolating means in response to the vacuum demand on the vacuum system being greatest, and advantageously, the operating signal is removed from the isolating means in response to the vacuum demand on the vacuum system reducing from the greatest demand.

In one embodiment of the invention the operating signal is applied to the isolating means in response to the milking system being operated for urging a cleaning liquid to flow through at least a portion of the milking system with full flow characteristics, and preferably, the operating signal is removed from the isolating means in response to the milking system ceasing to be operated for urging the cleaning liquid to flow through at least a portion of the milking system with full flow characteristics.

In another embodiment of the invention the operating signal is applied to the isolating means prior to the milking system being operated for urging a cleaning liquid to flow through at least a portion of the milking system with full flow characteristics, and preferably, the operating signal is removed from the isolating means subsequent to the milking system being operated for urging the cleaning liquid to flow through the at least portion of the milking system with the full flow characteristics.

The invention will be more clearly understood from the following description of an embodiment thereof, which is given by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a schematic representation of a vacuum operated milking system according to the invention, Fig, 2 is a transverse cross-sectional side elevational view of apparatus of the milking system of Fig. 1, Fig. 3 is a graphical representation of the air demand plotted against time of a vacuum system of the milking system of Fig. 1, and Fig. 4 is a graphical representation of air demand plotted against time of a vacuum system of a milking system similar to the milking system of Fig. 1 but operating according to the prior art.

Referring to the drawings and initially to Figs. ‘I and 2, there is illustrated a milking system according to the invention, indicated generally by the reference numeral 1.

The milking system 1 comprises a main milk pipeline 2 extending from an upstream end 3 to a downstream end 4 where the main milk pipeline 2 terminates in a receiver for receiving milk from the main milk pipeline 2, and through which a vacuum is applied through the receiver 5 to the main milk pipeline 2 by a vacuum system 8. A plurality of milking clusters 9, only one of which is illustrated in Fig. 1, are connected to the main milk pipeline 2 at spaced apart intervals along the main milk pipeline 2 by respective connecting pipes 10. A milk pump 11 pumps milk from the receiver 5 through a two-way solenoid operated valve 12 into a milk holding tank 14.

The vacuum system comprises a vacuum pump 15 which is driven by an electrically powered motor 16 and which applies a vacuum through a main vacuum line 18 to the receiver 5. A sanitary trap 19 located in the main vacuum line 18 removes milk and other particles which are drawn from the receiver 5 through a portion 20 of the main vacuum line 18. An interceptor 21 also located in the main vacuum line 18 removes any remaining liquids and particles not already removed by the sanitary trap 19. A regulator 23 in the main vacuum line 18 between the sanitary trap 19 and the interceptor 21 regulates the vacuum applied to the milking system 1.

A pulsator 24, which will be well known to those skilled in the art, for producing a pulsating vacuum is located in a secondary vacuum line 25 which is Teed off from the main vacuum line 18. The pulsating vacuum is applied from the pulsator 24 to the milking clusters 9 through corresponding connecting pipes 26 for pulsating milk liners (not shown) which are located within teat cups 27 of the milking clusters 9 for periodically relieving the pressure of the milk liners (not shown) on the teats of the animals for permitting blood to circulate in the animals’ teats during milking thereof.

A vacuum gauge in the secondary vacuum line 25 indicates the level of vacuum being applied by the vacuum system 8 in the main and secondary vacuum lines 18 and 25, respectively.

A wash and rinse water pipeline 30 is also provided and runs substantially parallel and adjacent the main milk pipeline 2 for accommodating washing and rinsing water from a wash trough 32 to apparatus 36 for accumulating a volume of washing water or rinsing water, depending on whether the milking system 1 is being operated in a washing or rinsing cycle, so that the volume of washing or rinsing water can be urged with full flow characteristics through the main milk pipeline 2 and the milking clusters 9 as well as the connecting pipes 10 connecting the milking clusters 9 to the main milk pipeline 2. The apparatus 36 for accumulating the volume of washing water or rinsing water is described in detail in Irish Patent Specification No. 81697 and British Patent Specification No. 2,316,290, and will only be briefly described below.

A plurality ofjetter units 33 are coupled to the wash and rinse water pipeline 30 at spaced apart intervals by connecting pipes 34. Although only one jetter unit 33 is illustrated in Fig. ‘l, the number of jetter units 33 is equal to the number of milking clusters 9, and each milking cluster 9 is provided with a corresponding jetter unit 33.

The jetter units 33 are adapted for coupling to the teat cups 27 of the corresponding milking clusters 9 for coupling the wash and rinse water pipeline 30 to the milking clusters 9 for facilitating the return of washing and rinsing water from the milking clusters 9 to the wash and rinse water pipeline 30 during washing and rinsing of the milking system 1.

The apparatus 36 comprises a cylindrical outer shell 37 closed at its respective opposite ends by top and bottom end caps 38 and 39, respectively. An inner cylindrical wall 40 extending upwardly from the bottom end cap 39 terminates in a weir forming upper edge 41 and defines with the cylindrical outer shell 37 an annular holding chamber 42 for holding a volume of washing water or rinsing water, depending on whether the milking system is operating in a washing or a rinsing cycle, which is urgeable through the main milk pipeline and the connecting pipes 10 and the milking clusters 9 to flow therethrough with full flow characteristics. An intermediate cylindrical wall 45 extending downwardly from an inner upper disc 46 which is spaced apart from the top end cap 38 divides the annular holding chamber into an inner annular compartment 47 and an outer annular compartment 48.

An inlet port 49 in the bottom end cap 39 accommodates washing or rinsing water from the wash and rinse water pipeline 30 into the annular holding chamber 42. An outlet port 50 in the bottom end cap 39 communicates with the annular holding chamber 42 through a central bore 51 defined by the inner cylindrical wall 40 for accommodating wash or rinse water from the annular holding chamber 42 which flows over the weir forming edge 41 formed by the inner cylindrical wall 40 into the main milk pipeline 2.

A vacuum operated solenoid controlled valve 52 mounted on the top end cap 38 is selectively operable for applying atmospheric pressure to the outer annular compartment 48 of the annular holding chamber 42, so that when the annular holding chamber 42 is substantially filled with washing or rinsing water, the continuous vacuum is applied to the main milk pipeline 2, and atmospheric pressure is applied to the outer annular compartment 48, the washing or rinsing water is rapidly discharged from the annular holding chamber 42 into the main milk pipeline 2 to flow therethrough with full flow characteristics. Under these conditions the washing or rinsing water also flows through the connecting pipes 10 and the milking clusters 9, similarly with full flow characteristics, and is returned to the wash and rinse water pipeline 30 through the corresponding jetter units 33 and the connecting pipes 34. Vacuum is applied to the valve 52 through a vacuum line 53 which is Teed off from the secondary vacuum line 25. A solenoid operated valve 54 is located in the wash and rinse water pipeline 30 adjacent the apparatus 36 for selectively coupling the wash and rinse water pipeline 30 to the apparatus 36 for washing and rinsing the milking system 1. As mentioned above, the apparatus 36 and its operation is already described in Irish and British Patent Specifications Nos. 81697 and 2,316,290, respectively.

Up to this, the milking system 1 and the vacuum system 8, as well as the apparatus 36 and the washing and rinsing water pipeline 30 is similar to that described in the Irish and British Patent specifications.

In order to minimise the power requirement of the vacuum system 8, an isolating means comprising a solenoid operated isolating valve 55 is located in the secondary vacuum line 25 between the pulsator 24 anda connection 58 through which the vacuum line 53 is coupled to the secondary vacuum line 25, for selectively isolating the pulsator 24 from the vacuum system 8 during periods of the washing and rinsing cycles of the milking system 1 while the vacuum demand on the vacuum system 8 is greatest. in this embodiment of the invention a control circuit 56 controls the milking system 1 and the vacuum system 8 during milking of the animals, and also controls the milking system 1 and the vacuum system 8 during washing and rinsing cycles of the milking system 1.

The control circuit 56 operates the milking system 1 and the vacuum system in conventional fashion during milking. During milking the control circuit 56 operates the solenoid valve 54 in the closed state in order to isolate the apparatus 36 from the main milk pipeline 2. During milking the solenoid operated isolating valve 55 is operated in the open state for applying the vacuum from the vacuum system 8 to the pulsator 24.

When it is desired to wash or rinse the milking system 1, the solenoid controlled valve 54 is operated in the open state to couple the apparatus 36 and in turn the main milk pipeline 2 to the wash and rinse water pipeline 30. Wash or rinse water is placed in the wash trough 32, and on applying the continuous vacuum to the receiver 5, the water in the wash trough 32 is drawn through the wash and rinse water pipeline 30 into the annular holding chamber 42 in the apparatus 36, and flows over the weir 41 formed by the inner cylindrical wall 40 and is drawn through the main milk pipeline 2. During this part of the washing or rinsing cycle the isolating valve 55 is operated in the open state in order to apply vacuum to the pulsator.

However, when it is desired to urge the wash or rinse water which has accumulated in the annular holding chamber 42 through the main milk pipeline 2 and the connecting pipes 10 and the milking clusters 9 with full flow characteristics, the vacuum powered solenoid operated valve 52 is operated to apply atmospheric pressure to the outer annular chamber 48 of the annular holding chamber 42 in order to urge the wash or rinse water through the main milk pipeline 2 and the connecting pipes 10 as well as the milking clusters 9 with full flow characteristics. The water flowing through the main milk pipeline 2 with full flow characteristics flows into the receiver 5 where it is in turn pumped by the milk pump 11 through the solenoid valve 12, which is operated to return the wash or rinse water to the wash trough 32. The vacuum applied to the milk pipeline 2 also draws the wash or rinse water from the wash and rinse water pipeline 30 through the connecting pipes 34, the jetter units 33, the milking clusters 9 and the connecting pipes 10, for washing and rinsing the milking clusters 9 and the connecting pipes 10.

In order to minimise the vacuum demand on the vacuum system during the washing and rinse cycles, shortly before, typically less than ten seconds prior to operation of the valve 52 for applying atmospheric pressure to the wash or rinse water in the annular holding chamber 42, an operating signal is applied by the control circuit 56 to the isolating valve 55 for operating the isolating valve 55 in the closed state for in turn isolating the pulsator from the vacuum system 8. The control circuit 56 continues to apply the operating signal to the isolating valve 55 in order to maintain the isolating valve 55 in the closed state for a short period, typically less than ten seconds, after the valve 52 has again been closed in order to isolate the annular holding chamber 42 from atmospheric pressure. On the ten seconds period having elapsed after the valve 52 has been closed, the operating signal is removed from the isolating valve 55, which again operates in the open state.

The vacuum demand placed on the vacuum system 8 is highest when the air demand is highest, and it has been found that the highest air demand occurs during the washing and rinsing cycle while the valve 52 is in the open state applying atmospheric pressure to the annular holding chamber 42 for driving the volume of wash or rinse water in the annular holding chamber 42 through the main milk pipeline 2, the connecting pipes 10 and the milking clusters 9 with full flow characteristics. Since pulsation of the milk liners (not shown) in the teat cups 27 is not required during washing or rinsing of the milking system 1, isolating the pulsator 24 during the period while the valve 52 is in the open state applying atmospheric pressure to the annular holding chamber 42 has no adverse effect on the washing or rinsing cycle. Indeed, it is envisaged in certain cases that the isolating valve 55 may be operated in the closed state for isolating the pulsator 24 from the vacuum system during the entire washing and rinsing cycles of the milking system 1.

Referring now to Figs. 3 and 4, the air demand on the vacuum system plotted against time during a washing cycle is illustrated for the milking system 1 according to the invention and for a milking system similar to the milking system 1 but operating according to the prior art. Both the milking system 1 according to the invention and the prior art milking system are sixteen unit systems, in other words, each of the two milking systems are sixteen milking cluster units. The graph of Fig. 3 represents the air demand on the vacuum system 8 of the milking system 1 according to the invention, while the graph of Fig. 4 represents the air demand on the vacuum system of the prior art milking system. In Figs. 3 and 4 the oscillating waveform A illustrates the air demand on the vacuum system of the two milking systems while the pulsator 24 is coupled to the vacuum system. The square waveform B represents the air demand on the vacuum system during the washing cycle while the valve 52 is operated in the open state for applying atmospheric pressure to the annular holding chamber 42. As can be seen from the graph of Fig. 3, by operating the isolating valve 55 of the vacuum system 8 of the milking system 1 in the closed state for isolating the pulsator 24 from the vacuum system 8 during the period while the valve 52 is operated in the open state, the maximum peak air demand drops from the peaks D of approximately 1,800 litres of air to approximately 1,400 litres of air during the maximum peak demand during the washing cycle, thereby providing an energy saving of approximately 22%. Similar savings are achieved during the rinsing cycle.

It has been found that the air demand on the vacuum system 8 by the pulsator 24 to produce the pulsating vacuum is typically 30 litres per minute per milking unit (milking cluster) on average. This air is used as a result of opening and closing of the liner, and peaks just as the liner is opened. The peaks occur at the pulsation rate, which typically is once per second. In a twenty unit milking installation the air required for pulsation is typically 600 litres per minute, while the air demand for cleaning is about 1,800 litres per minute where the milking system is fitted with a main milk pipeline 2 of 98mm diameter. The reserve for a twenty unit milking system is a minimum of 600 litres per minute and 800 litres per minute if automatic shut—off valves are not used in the milking clusters. Thus, the air demand during washing and rinsing of the milking system is approximately 1,800 litres per minute. By isolating the pulsator 24 while the valve 52 is operated in the open state for applying atmospheric pressure to the annular holding chamber 42, the air demand can be reduced from 1,800 litres per minute to 1,400 litres per minute, thus yielding an energy saving of 22%.

Additionally, by way of explanation, the energy used to provide vacuumised air in a milking parlour is dependent on the number of units. Some components of the air demand, such as air admission through the pulsator and the air admission through claws of the clusters, are calculated at a set amount per unit. There are also two air demands associated with the milkline, normal milking and cleaning. Normal milking requires an effective reserve which is nearly proportional to the number of units.

Cleaning air demand depends on the milkline size. The milkline size increases in predetermined steps. The points of change are based on published formula and standardised in tables in lSO5707. There are additionally losses that are calculated as a percentage of the total.

The size and number of vacuum pumps and associated motors is determined by the highest air demand, which is invariably during washing and rinsing. The peak consists of the washing and rinsing air demand associated with the milkline plus the other components for each unit. That peak demand is of a very short duration, a few seconds, compared to the normal operation of the milking system, namely, an hour or more. Reducing the peak air demand for those few seconds either allows the number of pumps and motors to be reduced or the pump and motor to be geared for lower power. Therefore, by reducing the peak air demand for that short duration allows an energy saving throughout the entire operation of the milking system.

While the method and apparatus according to the invention for minimising the power requirement of the vacuum system of a milking system has been described with reference to the milking system described in Irish and British Patent Specifications Nos. 81697 and 2,316,290, it will be readily apparent to those skilled in the art that the method and apparatus according to the invention may be used with any other milking system in which the vacuum demand is highest during washing and/or rinsing of the milking system.

The invention is not limited to the embodiment hereinbefore described, which may be varied in construction and detail.

Claims (5)

1. A method for minimising the power requirement of a vacuum system of a vacuum operated milking system, the method comprising isolating a pulsating vacuum generator of the milking system from the vacuum system during at least a portion of a cleaning cycle of the milking system, at least while the vacuum demand on the vacuum system is greatest.

2. A method as claimed in Claim 1 in which the pulsating vacuum generator is isolated from the vacuum system while the milking system is being operated for urging a cleaning liquid to flow through at least a portion of the milking system with full flow characteristics.

3. A method for minimising the power requirement of a vacuum system of a vacuum operated milking system, the method being substantially as described herein with reference to and as illustrated in the accompanying drawings.

4. A milking system comprising a main milk pipeline and a plurality of milking clusters connected to the pipeline, a vacuum system for applying a continuous vacuum to the main milk pipeline, and a pulsating vacuum generator coupled to the vacuum system for providing a pulsating vacuum for applying to the milking clusters, a washing means being provided for urging a cleaning liquid through at least a portion of the milking system, and an isolating means for selectively isolating the pulsating vacuum generator from the vacuum system in response to the vacuum demand on the vacuum system being greatest during a cleaning cycle of the milking system .

5. A milking system substantially as described herein with reference to and as illustrated in the accompanying drawings.