NZ231781A - Measuring milk yield by totalling discrete amounts: correcting for vacuum level in receiver - Google Patents

Description

23 1 7 Prioi'ty Date<s).' Complete Specification Filed: ...AU.Afcr.&'hv.- Class: £QX kgymlQL Publication Date: 2 ^ J UN 1992 P.O. Journal , no: Patents Form No. 5 A' v NEW ZEALAND , .. " V\ /' / PATENTS ACT 195 3 i </>/, C/-.

\ -• '• /Co • I COMPLETE SPECIFICATION ' #9. ->J \' r n METHCO OF DETERMINING QUANTITY OF MILK DRAWN BY MILKING INSTALLATION AND DEVICE THEREFOR ^We' LATVIISKAYA SELSKOKHOZYAISTVENNAYA AKADEMIA, a state-owned organisation existing under the law of the USSR, of Latviiskaya SSR, Elgava, ulitsa Lenina, 2, USSR, hereby declare the invention, for which Jsf/we pray that a patent may be granted to iiKS/us, and the method by which it is to be performed, to be particularly described in and by the following statement: (followed by Page la) la The present invention relates to milking facilities and, in particular, to methods of determining quantity of milk drawn by the use of a milking installation and to devices the refor.

The invention may find application in vacuum systems for milking cows and determining accurately the quantity of milk drawn therefrom to provide for effective zootechnic, veterinary and selective work with a dairy herd.

The main problem in determining the milk productivity of cows, total milk yield ana the amount of milk drawn from each cow and from a group of animals and in commercial milk record ing is low measuring accuracy attributable to unique and complicated characteristics of the measured medium (milk) and to the effect of specific conditions ana operating modes of milking installations.

Considerable difficulties are encountered in ensuring accurate milk-yield measurements due to the absence of requisite metrological facilities and to the lack of unified monitoring, testing and calibration techniques for the milk-yield measuring means. One of the principal factors decreasing accuracy in determining the quantity of milk drawn by the use of a milking installation is an unstable vacuum-gauge pressure therein in the course of milking. Sucn an unstable vacuum level in the milking system is generally attributable to variations of parameters of the measured mediur ■*+'n (followed by Page A "31 781 unstable operating modes of the vacuum system of a milking installation.

A known method (cf, SU, A, 657250) comprises the ste?3 of automatically measuring separate portions of milk by a float-type milk portioner inserted in a vacuum system of a milking installation, creating a difference between atmospheric pressure and vacuum-gauge pressure in the milking installation to transfer the measured portions of milk to a vacuum milk delivery line conmunicating with an evacuated milk collector, and recording the measured separate portions of milk by affecting mechanically with a movable rod of the milk portioner the drive of a mechanism counting said separate portions of milk.

In the disclosed method no account is taken of the effect of vacuum-gauge pressure on the accuracy in obtaining separate portions of milk, a disadvantage appreciably decreasing measuring accuracy.

Furthermore, in the aforesaid method separate portions of milk are recorded inaccurately due to the existing mechanical connection between the movable rod of the milk portioner and the drive of the counting mechanism, a factor introducing an adaitional measurement error.

Also, the aforesaid method does not provide for a single calibration and measurement technique to accurately measure the separate portions of milk in actual operation of milking installations whereby an additional error is introduced in measurements of separate portions of milk.

There is also known a device for determining the quantity ' 19 FEB 1992 of milk drawn by a milking installation (cf. SU, A, 657260), comprising a case accommodating feed and measuring chambers, a hollow rod having a lateral hole and a float secured to the rod, as well as a valve fixed on the lower end of the rod and contained within the measuring chamber. The upper end of the hollow rod is closed, while its lower end is open. The feed and measuring chambers are separated by a partition having a central hole through which said chambers communicate. As the hollow rod moves, its lateral hole is brought out of the case of the milk portioner at the moment said valve operates in the measuring chamber. After operation of said valve in the measuring chamber, the movable rod interacts with the drive of the mechanism counting separate portions of milk.

However, at the instant said valve operates and the hole in the partition is closed, an undetermined portion of milk is added to the measuring chamber due to the formed difference between vacuum-gauge pressure in the feed chamber and atmospheric pressure in the measuring chamber, a factor introducing error in counting off separate portions of milk. Moreover, there occurs an additional error in counting off separate portions of milk due to the mechanical connection between the movable hollow rod of the milk portioner and the drive of the mechanism counting separate portions of milk. The aforementioned device comprises no means adapted to adjust the milk portioner for an optimal portion of milk in actual operation of a milking installation on dairy farms.

Another known method of determining quantity of milk U \,drawn by a milking installation (cf. SU, A, 1345059) comprises the steps of computing a correlation factor by ^ dividing a known amount of milk into separate portions of milk; each portion corresponding to the maximum sensitivity of a discrete measuring means of the milking installation. The milk portions are then passed through the measuring means and the amount of milk passing through measured. The amounts measured by the measuring means are then summed and the correlation factor is obtained from the difference between the known amount and the summed amount. Milk is then passed through the milking installation and the amount of milk measured by the measuring means is corrected using the correlation factor. The corrected amounts are then summed.

In the aforementioned method, no account is taken of the effect of variations of vacuum-gauge pressure in the milking system on the obtained separate portions of milk, a disadvantage causing errors in determining the milk yield.

Another known device for determining quantity of milk drawn by a milking installation (cf. SU, A, 1345059) comprises a float-type discrete pickup used for measuring separate portions of milk and including a feed chamber having J inlet and outlet pipes and a measuring chamber having an outlet pipe, said chambers being separated by a partition having a hole, the measuring chamber accommodating a float secured to a hollow rod whose side wall has a hole located outside the feed, chamber and vented to the atmosphere when the hollow rod moves up to a predetermined point in the direction * o\\ f -^incident with the rising level of milk in the discrete pickup * 4 may i9<?2" I a magnet being disposed in close proximity to the closed end of the hollow rod, while a valve contained within the measuring chamber under the partition having said hole is arranged -\ in close proximity to the open end of the hollow rod, a milk receiver having its first inlet pipe connected with the outlet pipe of the measuring chamber of the discrete pickup and its second inlet pipe connected with the outlet pipe of the feed chamber of the discrete pickup whose inlet pipe is connected with a delivery line of a vacuum milk transfer system of a milking installation, an outlet pipe of the milk receiver being connected with the delivery line of the vacuum system of the milking installation, a computer, and a sensor aaaptea for summing up separate portions of milk and having its leads connected with a first input and with a first out-, put of the computer, said sensor being located in close proximity to the magnet secured to the hollow rod at the moment a predetermined milk level is reached in the discrete pickup. 3uch a device does not comprise means suited to monitor variations of vacuum-gauge pressure in the milking installation, a disadvantage leading to errors in determining optimal portions of milk.

The object of the invention is to create a method of determining the quantity of milk dravm by a milking installation and a device therefor, which would make it possible to take into account undetermined portions of milx in a measuring chamber in the event of variations of vacuum-gauge pressure in a milking installation whereby accuracy in determining .. * * /v < milk yield will be substantially increased. ~~4 $92 . . « - s This invention provides a method of determining the quantity of milk drawn by a milking installation, comprising: computing a correlation factor for a particular pressure by dividing a known amount of milk into separate portions of milk, each portion corresponding to the maximum sensitivity of a discrete measuring means of the milking installation, passing the milk portions through the measuring means at the particular pressure and measuring the amount of milk passing through it, summing the amounts measured by the measuring means, and obtaining a correlation factor from the difference between the known amount and the summed amount; repeating the previous step at a plurality of different pressures to obtain a correlation factor for each of a plurality of pressures; and passing milk through the milking installation while measuring the pressure in the milking installation, correcting the amount of milk measured by the measuring means using the correlation factor obtained for the pressure in the milking installation or the correlation factor obtained for a pressure immediately below the pressure in the milking installation, and summing the corrected amounts.

The invention also provides an apparatus suitable for carrying out the method, the apparatus comprising: a float-type measuring means that has a feed chamber, a measuring chamber separated from the feed chamber by a partition having a hole through it, and a hollow rod extending through the feed chamber and the hole and into the measuring chamber, the feed chamber having an inlet pipe connected to the delivery line of the vacuum transfer system of the milking installation and an outlet pipe, the measuring chamber having an outlet pipe, the ' •' hollow rod having a float mounted on it in the feed chamber, a o ^ v£l^e on it at its end in the measuring chamber, a sealed end at f':992 Hi •'317U its opposite, distal end and a vent hole in it adjacent its opposite, distal end, the hollow rod being reciprocally slideable between an open position in which the valve is clear of the hole in the partition and the vent hole is in the feed chamber and a closed position in which the valve seals the hole and the vent hole is outside of the feed chamber to vent the measuring chamber to atmosphere, and the hollow rod having a permanent magnet attached to it adjacent the vent hole; a milk receiver having a first inlet pipe connected to the outlet pipe of the measuring chamber, a second inlet connected to the outlet pipe of the feed chamber, and an outlet pipe connected to the delivery line of the vacuum transfer system of the milking installation; a computer means having calculation means to calculate the correlation factors for each pressure and storage means to store the correlation factors for each pressure; a detector means connected to the computer and positioned in close proximity to the permanent magnet on the hollow rod when the hollow rod is in its closed position so that the detector means detects and signals to the computer that the hollow rod is in its closed position; and a pressure detector in the milk receiver to measure the pressure in the milk receiver, the pressure detector being connected to the computer to transmit to the computer a signal corresponding to the pressure in the milk receiver; the computer means in use summing the signals obtained from the detector means and correcting the sum by selection and use of the correlation factor for the pressure in the milk receiver to determine the quantity of milk. 19 FEB 1992 The invention makes it possible to obtain accurate information, on the quantity of milk drawn by different types of milking installations on dairy farms. The use of information on the milk yield enhances effectiveness of zootechnic, veterinary and selective work with a dairy herd. The invention represents a novel and promising trend in the development of devices for determining milk yield, associated with the utilization of microprocessors and computers, a feature substantially increasing functional and metrological capabilities of technical means usea for measuring the quantity of milk drawn by milking installations. The use of accurate information obtained according to the invention permits increasing milk yield and saving labour in servicing milk counters, another advantage being enhanced reliability in milk-yield measurements.

Also, the" invent ion is suitable for use in automated control systems of dairy farms.

The utilization of means for monitoring measurements of a vacuum level in a milking installation and the relationship between the vacuum level in the milking system measured amount of milk permit making automatically a final correction of previously corrected separate portions of milk while the cows are milked by the use of milking installations in actual operation, a feature appreciably increasing accuracy in determining quantity of milk drawn by milking installations.

The invention will now be described further with reference to a specific embodiment thereof, taken in conjunction with the accompanying drawings, wherein: Fig. 1 is a general view of a device for determining the quantity of milk drawn by a milking installation at the moment a portion of milk is counted off by a discrete pickup with an electronic computer for recording and correcting the quantity of obtained milk, according to the invention; Fig. 2 shows the discrete pickup at the moment a measuring chamber is filled with milk, according to the invention; Fig. 3 is a block diagram of the computer, according to the invention; and Fig. 4 is a functional diagram of the computer, according to the invention.

The following operations are performed to carry out the proposed method of determining the quantity of milk drawn by a milking installation. A preliminary adjustment is made to form optimal portions of milk corresponding to maximum sensitivity of the discrete measuring means (referred to as a "discrete pickup") of the milking installation. Depending on a desired measuring accuracy and on the purpose ^,of collecting information on quantity of milk, an optimal -TV (portion of milk is determined to comply with maximum sensitiv- "31781 ity of che discrete pickup of the silking installatio: actual operation. To this end, reference measurements are made by the discrete pickup with a view to obtaining a standard amount of freshly drawn silk to suit the purpose of the measuring procedure. To record individual yields from each cow, a standard amount should include freshly drawn milk of a single yield. To determine milk yield from a group of cows, a standard amount of milk should be equal to the measured quantity of milk drawn from a group of cows. A3 is known from the theory and practice of liquid-media flow and quantity measurements, a minimum quantity of measured milk, for example, in recording individual milk yields corresponds to maximum sensitivity of a measuring means (discrete pickup in the method, according to the invention). Therefore, an optimal portion of milk corresponding to the maximum sensitivity of the discrete pickup is chosen to ensure a desired measuring accuracy and, in effect, a minimum measurement error for a given type of milking installation in actual operation.

To preadjust the discrete pickup of the milking installation for formation of optimal portions of milk, the chosen standard amount of milk may comprise all of the milk freshly drawn from one cow. Such a milk yield should be initially weighed using a balance with a scale graduation not in excess of 1/6 of the tolerance of a desired milk-yield measuring accuracy to comply with the requirements for milk-yield data, specified by zootechnicians, veterinsry surgeoas and breeders In a further operation, milk freshly drawn from one cow ; -• PAlP|\rr OFFICE 19 FEB 1992 f .1 ! / 0 i 11 and used as a standard is passed through the discrete pickup, for example, with the help of a milking unit operating under design conditions, immersed in a standard amount of freshly drawn milk. Under pulsating vacuum conditions, the operating milking unit is utilized to extract the standard amount of freshly drawn milk, which is fed to the discrete pickup. This provides for stimulation of real milking with natural milk newly drawn from one cow. As the discrete pickup automatically meters portions of the standard amount of milk to stimulate real milking with freshly drawn milk, said standard amount of milk is divided into separate portions.

Thus, the standard amount of milk during calibration of the discrete pickup is milk freshly drawn from one cow and weighed to a required accuracy at the initial stage. Agreement is, therefore, provided between the mathematical and physical models of the process involving measurement of milk yield obtained by the use of milking installations. On completion of stimulated milking, the computer is used to sum up the separate portions of the standard amount of milk and to determine the difference between the standard amount of freshly drawn milk and the calculated sum of separate portions of the standard amount of milk. The obtained difference is used to calculate a correlation factor for each separate portion of milk. This process is repeated at a plurality of pressure levels to obtain a plurality of correlation factors; one for each pressure.

In the mean (operating) mode the proposed method of determining quantity of milk drawn by a milking installation is ^subsequently accomplished as follows. Variations of vaccum-gauge pressure in the milk receiver of the milking installation / rtHl 12 and in the discrete pickup cause changes in the separate portion of milk in the discrete pickup. This results in the amounts of milk received in the discrete pickup changing unpredictably. To account for this, it is necessary to make allowances for these changes when the vacuum level in the milking installation changes. To take due account of the milk-yield measurement error due to variations of the vacuum level in the milk receiver of the milking installation, the correlation factors are used to correct the measured amounts of each portion. It will be appreciated that different types of correlation factors can be used. A preliminary correction factor can be used to convert the analogue signal from the discrete pickup to a weight measurement and a final correlation factor can be used to correct for the pressure. Alternatively a single correlation factor, for each pressure, can be used to convert the analogue signal directly to a corrected weight measurement.

The proposed device for determining the quantity of milk drawn by a milking installation comprises a float-type discrete pickup 1 (Fig. 1) used for measuring separate portions of milk 2 and including a feed chamber 5 having an inlet pipe 6 and an outlet pipe 7 and a measuring chamber 8 having an outlet pipe 9, said chambers being separated by a partition 3 having a hole 4. The feed chamber 5 accommodates a float 10 secured to a hollow rod 11 having in its side wall a hole 12 located outside the feed chamber 5 and vented to the atmosphere as the hollow rod 11 moves up to a predetermined point in the 11, / direction coincident with the rising level of the milk 2 •in the discrete pickup 1. In the drawing, the arrow "a" shows the direction in which the level of the milk 2 increases.

A permanent magnet 13 is fixed by a fastener 14 in the vicinity of the closed end of the hollow rod 11, whereas a valve 15 placed in the measuring chamber 8 under the partition 3 is secured in close proximity to the open end of the hollow rod 11. The valve 15 may be fabricated from an elastic material, for example, rubber.

The device for determining quantity of milk drawn by the use of a milking installation, according to the invention, further comprises a milk receiver 16 whose inlet pipe 17 is connected via a pipeline 18 with the outlet pipe 9 of the measuring chamber 8 of the discrete pickup 1. An inlet pipe 19 of the milk receiver 16 is connected via a pipeline 20 with the outlet pipe 7 of the feed chamber 5 of the discrete pickup 1. The inlet pipe 6 of the feed chamber 5 is connected with a delivery line 21 of a vacuum milk transfer system of the milking installation. An outlet pipe 22 of the milk receiver 16 is connected with a delivery line 23 of the vacuum system of the milking installation.

The milk receiver 16 has a hollow rod 24 in it that is made of a nonmagnetic material. A float 25 is mounted on the rod 24 and is arranged in a manner allowing its movement along the rod 24 as the milk receiver 16 is filled with the milk 2, that is, when the level of the milk 2 in the milk receiver 16 changes. The float 25 is .-..provided with a magnet 2 6 interacting with sealed-contact reecf^relays 27, 28 used, respectively, to engage and disengage -U- '317b for its primary processing. la the drawing, the arrows "b" show the direction of movement of the liquid fraction of the ailk 2 ■ in the milking installation, -vr.ile arro.vs "c" show the direction of movement of the gas-air fraction of the milk 2.

The proposed device for determining the quantity of milk drawn by a milking installation also includes a computer 31 comprising a microprocessor 32, a digital indicator 33 connected to the microprocessor 32, a digital printer 34 connected. to the microprocessor 32, and a detector 35 adapted for summing up separate portions of milk and having its leads connected to a first input and to a first output of the computer 31 , said detector being arranged in close proximity to the permanent magnet 13 secured to the hollow rod 11 at the moment a predetermined milk level is reached in the discrete pickup 1. The detector 35 is secured to a bracket 36.

The proposed device for determining the cjuantity of milk drawn by the use of a milking installation further comprises a vacuum gauge 37 communicating with the milk receiver 16 and intended for measuring the pressure *-n ^'ae ^il'^ receiver 15 of the milking installation, said vacuum gau~e producing control signals enabling a final correction of previously corrected separate portions of the milk 2 and dependent on variations of the pressure in the milk receiver 16. The vacuum gauge includes an indicator 38 adapted for indicating the pressure in the milk receiver'1o and mounting a permanent magnet 39 and a group of sealed-contact reed relays 40^, 4-021 whose number depends on the chosen discreteness level of separately corrected portions of milk witn respect to the pressure in the milk receiver 16 . In the preferred embodiment of the ^ invention the number of sealed-contact reed relays (n) is five.

The first and second leads of each sealed-contact reed relay 40^, 402/ 404 and 40,. are connected, respectively, to the input and to the output of the computer 31. The indicator 38 is mounted on a shaft 41.

When cows are milked by a milking installation, the feed chamber 5 and the measuring chamber 8 of the discrete pickup 1 and a portion of the pipeline 18 are filled with the milk 2 which is fed to the milk receiver 16 of the milking installation while separate portions of milk are being metered. In the drawing arrow "d" shows the direction of air flowing through the hole 12 in the hollow rod 11 at atmospheric pressure.

At the moment the measuring chamber 8 (Fig. 2) begins to fill with milk, the hole 12 in the hollow rod 11 is found inside the feed chamber 5 of the discrete pickup 1, while the magnet 13 is located beyond its zone of interaction with the detector 35 adapted for summing up separate portions of milk.

The proposed device for determining quantity of milk drawn by a milking installation also comprises a microprocessor initial adjustment and power supply unit 42 whose input and outputs are connected, respectively, to the output and to the inputs of the microprocessor 32.

The microprocessor 32 using known circuitry includes a control unit 43 (Fig. 3) having its first and second outputs ,. ^ v*-"* c-and its first input connected to the digital printer 34, a /y <■ ^ memory unit 44 comprising an adress register 45 whose input ^ may J992rr- 231781 and output are connected, respectively, to a third output and to a second input of the control unit 43, a memory element 46 having its input connected to the output of the address register 45, an instruction register 47 having its input connected to the output of the memory element 4 6 and its output connected to a third input of the control unit 43, and a group 48 of on-line memory registers whose number depends on the number of controllable vacuum levels in the milk receiver 16 (Fig. 1), that is, on the numbei* of sealed-contact reed relays 40^ (Figo 3), 402, ...40^, a multichannel input-output of the group 48 being connected to a multichannel input-output of the control unit 43.

The microprocessor comprises an arithmetic unit 49 having ics first and second inputs and its output connected, respectively, to fourth and fifth outputs and to a fourth input of the control unit 43.

Furthermore, the microprocessor includes an accumulator register 50 whose input and output are connected to a sixth output and to a fifth input of the control unit 43, ail indicator register 51 having its inputs connected to seventh and eighth outputs of the control unit 43, and a decoder 52 having its input connected to the output of the indicator register 51 and its multichannel output connected to the first multichannel input of the digital indicator 33 whose second multichannel input is connected to the control unit 43.

The microprocessor initial adjustment and power supply unit 42 comprises a circuit 53 intended for initial setting of the microprocessor elements, a voltage converter circuit 231781 54 having its first output connected to a first input of the circuit 53 intended for initial setting of the microprocessor elements and having its first &nd second outputs connected to sixth and seventh inputs of the control unit 43, and a power supply unit 55 having its first input and its output connected, respectively, to a second output and to a first input of the voltage converter circuit 54, while second and third inputs of the power supply unit 55 are connected with terminals 56 of an AC voltage source (not shown in the drawing). The second input of the circuit 54 is connected to a ninth output of the control unit 43. The output of the power supply unit 55 is connected to a second input of the circuit 53.

Moreover, the proposed device for determining quantity of milk dra'-vn by a milking installation comprises a clock frequency generator 57 having its inputs connected to third and fourth outputs of the circuit 53 intended for initial setting of the microprocessor elements and its output connected to an eighth input of the control unit 43.

The digital printer 34 (Pig. 4) includes an actuating unit 58 and control signal amplifiers 59, 6C having their inputs connected to the microprocessor 34 and their outputs connected to the inputs of the actuating unit 58, while the output of the actuating unit 58 is connected to the input of the microprocessor 32.

The circuit 53 intended for initial setting of the microprocessor elements comprises an assembly 61 used to adjust the microprocessor elements, a time-setting network incorporating a resistor 62 and a capacitor 63 and connected to the 23178 clock frequency generator 57, and a variable resistor 64 used to set a required voltage at the output of the microprocessor 32.

The power supply unit 55 comprises a circuit 65 enabling connection to an external supply line, a limiting resistor 66, a cell 67, and a diode 68. One lead of the resistor 66 and the anode of the diode 68 are joined together and connected to the input of the circuit 65, wherea3 the cathode of the diode 68 is coupled to one lead of the cell 67 and connected to the second output of the voltage converter circuit 54. The other lead of the cell 67 is connected to the output of the circuit 65 and to the first data input of the microprocessor 32. The other lead of the resistor 66 is connected to the first input of the circuit 54t to the second input of the circuit 53 and to the second data input of the microprocessor 32.

The device for determining quantity of milk drawn by a milking installation, according to the invention, operates as follows.

At the preliminary stage real milking is simulated using a standard amount of freshly drawn milk with the milking installation operating unaer design conditions. To do this, a standard amount of milk equalling a single yield from one cow is initially weighed to an accuracy corresponding to 1/6 of the tolerable value to suit the requirements for determining quantity of milk drawn by a milking installation. Such a precision in obtaining said standard amount of milk provides for desired accuracy in making a preliminary adjustment of 2 5 17 8 1 the discrete milk pickup, for example, the float-type pickup, according to the invention.

A vacuum regulator (not shown in the drawing) of the milking installation is used to set a predetermined vacuum level in the milk receiver 16 (Fig. 1) of the milking installation, corresponding to rated operating conditions complying with the requirements for pnysiology of machine milking. In the preferred embodiment of the invention the nominal (recommended) vacuum level in the milk receiver 16 of the milking installation is about 0.53 kgf/cm".

Real milking is simulated on completion of preliminary operations involving regulation of milking conditions. This can be done by immersing the milking unit in a standard amount of milk with the operating pulsator (not shown in the drawing). As a result, freshly drawn milk 2 is fed over the delivery line 21 to the feed chamber 5 of the discrete pickup 1, whence it flows through the hole 4 in the partition 3 of the pickup 1 into its measuring chamber 8. A3 the operation of the milking unit continues, the accumulated milk 2 completely fill9 the measuring chamber 8. Flowing on the underside through the hole 4 in the partition 3 of the pickup 1 into the feed chamber 5 the milk lifts the float 10 mounting the valve 15, the hollow rod 11 with the hole 12 and the permanent magnet 13. The level of the milk 2 in the feed chamber 5 will increase until the hole 12 in the rod 11 of the float 10 leaves the feed chamber 5. At this moment the valve 15 closes the hole 4 in the partition 3 separating the measuring chamber 8 from the feed chamber 5 of the pickup 1. - 20 - '?:> i 7 o ! The feed chamber 5 is, at this time, in communi-cation with the milk receiver 16 and the pressure in the s chamber 5 corresponds to the pressure in the milk receiv- p er 16 and equals the recommended value (about 0.53 kgf/cm ) for a given type of milking installation. When the hole 4 is closed by the valve 15, the pressure -—— affects the fo mat ion of portions of the milk 2 in the measuring chamber 8 said effect being unaccounted for in the metering of the milk 2 in the measuring chamber 8. Consequently, the amount °~ the nil* 2 —^in the measuring chamber 8 cannot be determined for the pressure of 0.53 kgf/cm^ in the milk receiver 16, a factor substantially decreasing accuracy in determining quantity of milk drawn by milking installations. Thereafter the — milk 2 contained in the measuring chamber 8 is automatically fed to the milk receiver 16 via the outlet pipe 9 ana the pipeline 18 due to the difference between the vaccum-gauge O pressure (P =» 0.53 kgf/cn ) in the milk receiver 16 —= and the atmospheric pressure ?? supplied to the measuring chamber 8 through the hole 12 in the hollow rod 11. Air from the milk flow fed through the inlet pipe 6 of the feed chamber 5 : is discharged into the milk receiver 16 via the chamber 5, the outlet pipe 7 and tne pipeline 20 bypassing the measuring chamber 8. Thus, the standard , £ n /"'amount of freshly drawn milk is continuously divided into o\. / separate undetermined portions at the preset pressure n * ^ May 1992 A / V r O / C [ *' C O V ! O i / , ' 2 = 0.53 kgf/cm in the milk receiver 16. The total number of the separate undetermined portions of milk is calculated by the > use of the detector 35 which stuns each separate portion of milk and signals the computer 31, each signal being representative of the separate portion of milk.

Each undetermined portion of milk, which is approximately equal to the capacity of the measuring chamber 8 is recorded by the computer 31 and is fed to the milk receiver 16 under the action of atmospheric pressure. Due to the communication between pipelines 18 and 20, the vacuum-gauge pressure in the chambers 5 and 8 is equalised through the inlet pipe 17 of the milk receiver 16. As a result, the milk 2 is removed from the feed chamber 5 and from the measuring chamber 8. Also the float 10 and the valve 15 will automatically go down by gravity. The hole 12 in the hollow rod 11 is brought into the feed chamber 5 while the valve 15 opens the hole 4 in the partition 3. Consequently, the measuring chamber 8 receives another undetermined portion of the standard amount of milk and the process of reproducing and recording separate undetermined portions of the milk 2 is automatically repeated in the course of simulated milking until all milk of the standard amount is *"*' passed through pickup 1. Next, there is determined the difference between the standard amount of freshly drawn milk used in simulated milking and the sum of separate undetermined portions recorded by the computer 31. & , t , 1 c 'C V 7 *^\ « - !: '4 MAY 1992^/j The results obtained in a series of consecutive operations are used to make a preliminary correction of separate uncontrollable portions of the milk 2 whereupon previously corrected separate portions of the milk 2 are summed up by the computer 31.

In the afore-mentioned operations, account is taken only of structural peculiarities of the pickup 1 and of the properties of the measured medium (milk 2) at the constant vacuum level P1 in the milking system, more specifically, in the milk reciever 1o. This appreciably limits accuracy in determining separate portions of the milk 2 and in measuring the total yield of the milk 2 drawn by milking installations since in actual milking by the use of milking installations the vacuum level in the milk receiver 16 changes within wide limits, a factor causing undetermined variations of separate portions of milk and decreasing milk-yield measuring accuracy.

In milking installations under consideration, changes in the vacuum level may be attributed to load variations in the vacuum system (not shown in the drawing), for example, depending on the number of cows being milked simultaneously and also due to operational troubles (air inflow at joints of the milk pipeline, air inflow in connection of the milking units, clogging of the vacuum system) and technical faults (local malfunctioning of elements of the milking installation). Under operating conditions, the vacuum level in the milk ck * i-<» receiver 16 may, for example, change within the follovYing * c ? * range: ?1 - 0.45 to 0.55 kgf/cm . With such variations of the vacuum level, it is possible to take into account separate portions of the milk 2 in the measuring chamber 8 of the pickup 1 depending on the actual vacuum level in the milking system in the course of milking.

In compliance with the invention the preliminary correction factors corresponding to the corrected separate portions of milk and obtained during each simulated milking cycle make up as a sum a standard amount of freshly drawn milk passed via the pickup 1 in simulated milking. Each separate simulated milking cycle ends with computing a predetermined optimal factor for correcting a separate portion of milk with several (for example, five) successively set vacuum levels in the milk receiver 16. The preliminary correction factors obtained by calculations in simulated milking are inserted manually in the microprocessor 32, more specifically, in the group 48 of on-line memory registers before actual milking begins. This completes the preliminary stage according to the invention.

In actual milking, according to the invention, formation of previously corrected separate portions of the iiiilk 2 (Fig. 1) occurs simultaneously with automatic measurements of the vacuum level in the milk receiver 16 of the milking installation corresponding to said previously corrected separate portions of the milk 2. When the previously corrected separate portions of milk are summed up, a final correction is made of each previously corrected separate portion of milk taking into account the vacuum level in the milk receiver 16 of the milking installation corresponding to said portion.

The milking unit (not shown in the drawing) is connected 1 24 to the cow's udder and the milking begins. In much the same manner as during the preceding stage, freshly drawn milk is fed via the delivery line 21 of the milking installation by way of the pipe 6 to the measuring chamber 8 of the pickup 1 whence the accumulated milk is supplied through the hole 4 in the partition 3 to the feed chamber 5, in which it affects the float 10. At the same time, the hollow rod 11 and the float 10 move upwards until the hole 12 in the hollow rod 11 leaves the feed chamber 5 of the pickup 1 whereby the valve 15 of the hollow rod 11 will close the hole 4 in the partition 3. The actual vacuum level in the milk receiver 16 is simultaneously measured with the vacuum gauge 37. A corresponding electrical signal is fed to the computer 31 during the measurement of the actual vacuum level in the milk receiver 16 owing to the fact that the scale of the vacuum gauge 37 is provided with sealed-contact reed relays 40^, 402/ 40^, 404 and 40^ connected to the respective inputs and outputs of the computer 31 and also due to the presence of the permanent magnet 39 on the vacuum level indicator 38. Said electrical signal is produced as the permanent magnet 39 on the indicator 38 energizes one of the sealed-contact reed relays 40^, 402, 40^, 404, 40,. used to select optimal portions corresponding to the existing vacuum level in the milk receiver 16. The respective circuit of the control unit 4 3 (Fig. 3) of the microprocessor 32 is completed and the group 48 of its on-line memory registers automatically transmits via the unit 43 to the digital indicator 3 3 the numeric value of an optimal separate portion of the milk 2 1) corresponding to the current vacuum level in ■•4MAY1992 n ■ the milk receiver 16, for example, depending on the position of the sealed-contact reed relay 40^ on the scale of the indicator 38 of the vacuum gauge 37. At the same time, atmospheric pressure affects the portion of the milk 2 in the measuring chamber 8 through the hollow rod 11, thus forcing said portion out into the milk receiver 16 through the pipe 18. The sealed-contact reed relay of the detector 35 operates when affected by the field set up by the magnet 13 whereby the respective circuit of the control unit 43 (Fig. 3) of the microprocessor 32 is completed and previously corrected separate optimal portions of the milk 2 (Fig. 1) corresponding to the current vacuum level in the milk receiver 16 are summed up. The results obtained in summing up said separate optimal portions of the milk 2 are continuously recorded by the digital indicator 33.

As the vacuum level in the milk receiver 16 is measured without interruption, due account is made of the portions of the milk 2 in the measuring chamber 8 of the pickup 1, which were undetermined at the preliminary stage, by making continuously a final correction of said separate portions of the milk 2 in the pickup 1 throughout the milking process.

If the vacuum level in the milk receiver 16 changes to correspond, for example, to the position of this indicator 38 on the scale of the vacuum gauge 37 reading, for example 2 0.48 kgf/cm , which corresponds, say to the position of the sealed-contact reed relay 40^ on the scale of the vacuum gauge 37, the magnet 39 of the indicator 38 will close the respective circuit of the control unit 43 (Fig. 3) of the ■4 MAY 1992 microprocessor 32 and the ^roup -8 of on-line memory registers v/ill automatically feed Tia the unit A3 to the digital indicator 33 the numeric value of the previously corrected separate optimal portion of the milk 2 (Jig. 1) corresponding to 2 the vacuum level of 0.48 kgf/cm . In this case the detector 3 5 used for summing up separate portions of milk ".vill sum up the signals coming from the pickup 1 taking into account the actual vacuum level in the milk receiver 15. On completion of milking, the silk yield is recorded by the unit 34.

Thus, a final correction of previously corrected separate portions of milk during their formation in the discrete pickup 1 makes it possible to e.ccount for undetermined portions of the milk 2 in the measuring chamber 8 in the event of variations of vacuum-gauge pressure in the milking installation, an advantage generally increasing accuracy in determining the quantity of milk dravm by milking installations.

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Claims (10)

WHAT WE CLAIM IS -27-

1. A method of determining the quantity of milk drawn by a milking installation, comprising: computing a correlation factor for a particular pressure by dividing a known amount of milk into separate portions of milk, each portion corresponding to the maximum sensitivity of a discrete measuring means of the milking installation, passing the milk portions through the measuring means at. Jbhe particular pressure and measuring the amount of milk passing through it, summing the amounts measured by the measuring means, and obtaining a correlation factor from the difference between the known amount and the summed amount; repeating the previous step at a plurality of different pressures to obtain a correlation factor for each of a plurality of pressures; and passing milk through the milking installation while measuring the pressure in the milking installation, correcting the amount of milk measured by the measuring means using the correlation factor obtained for the pressure in the milking installation or the correlation factor obtained for a pressure immediately below the pressure in the milking installation, and summing the corrected amounts.

2. A method according to claim 1 in which the known amount of milk is the quantity of milk freshly drawn from a cow and weighed on a scale.

3. A method according to claim 1 or claim 2 in which the correlation factors are stored in a computer means.

4. A method according to any one of claims 1 to 3 in which a correlation factor is obtained for each of five separate pressures. c 3 1 7 b 1 -28-

5. A method according to any one of claims 1 to 4 in which the measuring means includes a movable level indicator, the ^ amount of milk measured in the measuring means being calculated from a count of the number of times that the level indicator reaches its maximum level.

6. A method according to claim 1 and substantially as described in this specification.

7. An apparatus suitable for carrying out the method of claim 1, the apparatus comprising: a float-type measuring means that has a feed chamber, a measuring chamber separated from the feed chamber by a partition having a hole through it, and a hollow rod extending through the feed chamber and the hole and into the measuring chamber, the feed chamber having an inlet pipe connected to the delivery line of the vacuum transfer system of the milking installation and an outlet pipe, the measuring chamber having an outlet pipe, the hollow rod having a float mounted on it in the feed chamber, a valve on it at its end in the measuring chamber, a sealed end at its opposite, distal end and a vent hole in it adjacent its opposite, distal end, the hollow rod being reciprocally slideable between an open position in which the valve is clear of the hole in the partition and the vent hole is in the feed chamber and a closed position in which the valve seals the hole and the vent hole is outside of the feed chamber to vent the measuring chamber to atmosphere, and the hollow rod having a permanent magnet attached to it adjacent the vent hole; a milk receiver having a first inlet pipe connected to the outlet pipe of the measuring chamber, a second inlet connected to the outlet pipe of the feed chamber, and an outlet pipe connected to the delivery line of the vacuum transfer system of the milking installation; 23178 1 -29- a computer means having calculation means to calculate the correlation factors for each pressure and storage means to store the correlation factors for each pressure; a detector means connected to the computer and positioned in close proximity to the permanent magnet on the hollow rod when the hollow rod is in its closed position so that the detector means detects and signals to the computer that the hollow rod is in its closed position; and a pressure detector in the milk receiver to measure the pressure in the milk receiver/ the pressure detector being connected to the computer to transmit to the computer a signal corresponding to the pressure in the milk receiver; the computer means in use summing the signals obtained from the detector means and correcting the sum by selection and use of the correlation factor for the pressure in the milk receiver to determine the quantity of milk.

8. An apparatus according to claim 7 in which the pressure detector includes a pressure gauge, the movable pointer of the pressure gauge having a permanent magnet attached to it and the pressure gauge having a plurality of sealed-contact reed relays spaced about the gauge and each activated by the permanent magnet on the pointer to produce a signal corresponding to the pressure in the milk receiver.

9. An apparatus according to claim 8 that has five sealed-contact reed relays.

10. An apparatus according to claim 7 and substantially as described in this specification with reference to the drawings. LATVII^KAYA SELSKOKHOZYAISTVENNAYA AKADEMIA