Method and device for determining the milk quality

Abstract

The invention relates to a method and device, determining the milk quality, for the rapid and precise determination of the fat content and the dry non-fat residue in it. The method consists in continuous measurement at intervals of 30μs to 300 ms during the heating of the test sample up to 64° C, measuring the ultrasound speed Vus, the reported values of the voltage Uh, and the current strength Ih of the heater (4), calculating the energy, released by the heater E1n. The data serve for mathematical stepless determining the least fat content of milk, dry non-fat residue of milk and protein content in milk; The device contains a control module (10), maintaining a two-way connection with a current sensor (7) that continuously measures the heater current during the heating process, as the control module makes calculations, using the reported values received from it.

Description

[0001] DESCRIPTION

[0002] OF METHOD AND DEVICE FOR DETERMINING THE MILK QUALITY

[0003] FIELD OF TECHNOLOGY

[0004] The invention relates to a method and device for determining the milk quality, for the rapid and precise determining the fat content, the content of dry non-fat residue and the content of protein in it. The field of technology is the dairy industry, as well as the control of food liquids.

[0005] It is used in measurements at milk acceptance points, milk processing enterprises, in the field of control of food products and goods by the relevant control bodies;

[0006] THE BACKGROUND OF THE INVENTION

[0007] A device for determining the fat content and the dry non-fat residue of milk is known and includes a processing and control unit, connected to a measuring unit. The measuring unit is two-chamber, as both chambers are identical and consist of a measuring chamber with a heater and a thermostat, as well as of an ultrasound source / receiver. The device is equipped with a hopper for the measured fluid, connected to each of the measuring chambers, and between the hopper with the fluid and each of the measuring chambers separately, coils are located, also equipped with heaters for preparatory tempering, before the sample for measurement enters the measuring chamber. The pairing of the chambers allows the parallel performance of two measurements simultaneously, at different sample temperatures.

[0008] The device operates as follows: through the pumps of both parallel channels, from the hopper with the measured fluid, the milk passes through both coils, fills both measuring chambers and part of the equalizing vessels. The preliminary tempering and preparation for the actual measurement are carried out in the coils.The first coil tempers the sample for measurement to 41 °C, the second coil, through its heater, tempers the sample for measurement to 65°C. In the measuring chambers, thus prepared samples are subjected to ultrasonic emission with a certain frequency, which is received by the ultrasonic receivers, and after processing the information in the control unit, the ultrasonic speeds of both samples are determined. On the grounds of the reported measurements, the fat content and the dry non-fat residue are calculated, as the report is carried out only on the basis of two values of the ultrasonic speed. Patent BG 64468 B1;

[0009] Disadvantage of the known device and method is that the device measures two samples with two different temperatures. The limited number of temperatures means a limited set of primary data, which in turn leads to a limited number of measured parameters of the tested sample, in this case - fat content and dry nonfat residue content. The presence of two chambers, two pre-heaters and two pumps leads to increase in the cost of the device, as well as to more heat released and more energy consumption. The use of two separate measuring chambers can also have a negative impact on the accuracy and reliability of the device.

[0010] It is known a method for milk analysis in determining the fat content and dry nonfat residue in milk, which consists of determining the temperature of the analyzed milk sample or of the milk is heated to a precisely defined temperature;

[0011] At the same time, a laser beam with certain intensity is emitted and the intensity of the light transmitted through the milk sample and the intensity of the scattered light at a certain angle are measured;

[0012] After determining the temperature or reaching a set temperature, ultrasound is emitted in the same milk sample with a certain frequency and its speed and attenuation in the milk sample are measured;

[0013] If additional parameters need to be measured, the milk is heated to (n-1) more temperatures, and at the precisely established temperature / s, ultrasound is emitted and its speed and attenuation in the milk sample are measured at each temperature;The parameters of the milk are derived as a function of, on the one hand - the values of speed and scattering of ultrasound, and on the other hand - of the ratio of transmitted-scattered light of the laser beam. A system of a certain number of equations is composed and by its mathematically solving, the milk parameters are determined. The number of equations in the system depends on the total number of parameters obtained from both types of measurements - ultrasonic and laser. Patent application BG110521 A1;

[0014] Disadvantage of the known device and method is the complication and, accordingly, the increase in cost of the device, due to the combination of two different measurement principles. If the measurements are performed stepwise, for obtaining n-1 number of measurements at different temperatures and a larger data information matrix, it is on the account of significant increase in the measurement time.

[0015] The task of the invention is to create a method, and a simple and inexpensive device for determining the milk quality and quick complex milk analysis, by measuring multiple specific values of the composition of the measured sample in a short period of time. The measurement should be carried out with continuous heating of the sample, without waiting for the temperature to be established at separate fixed values, whereby providing a solid data information matrix in a short time, which would serve for quick and accurate determination of more components determining the milk quality, for example, fat content, dry non-fat residue and protein in the measured sample.

[0016] SUMMARY OF THE INVENTION

[0017] The task of the invention is solved by a method for determining the milk quality, according to which the device operates, and which consists of: A part of the measured food fluid is sucked by a pump from a feed hopper, which fills a measuring chamber, until it is completely filled, together with a part of an expansion tank, connected to it, and this amount constitutes a test (measured) sample - continuous uniform heating of the tested (measured) sample, by a heater,to a set final heating temperature in the range from 60°C to 64°C; The ultrasound speed - Vus is measured periodically with a set sampling period from 30μs to 300ms, but continuously for the entire time of heating the sample until reaching a final heating temperature in the range from 60°C to 64°C;

[0018] During the heating period of the sample, from the beginning until reaching the final temperature from the heating range of 60°C to 64°C and without interruption within this period, but with the set sampling period of 30μs to 300ms, the control module measures and reports the heater voltage Uh and the heater current Ih; As a function of each of the measured values of the voltage Uh and the current Ih of the heater, for each discrete interval from 30μs to 300ms, the corresponding heater power Ph and the corresponding heater resistance Rh are determined;

[0019] At the same time, the heater resistance Rh determines the heater temperature Th. Through the determined values of the heater temperature Th and the heater power Ph, by means of the simplified heat exchange model, shown in Fig. 3, the temperature of the sample Ts, which is in the measuring chamber heated by the heater, is determined for each discrete interval from 30μs to 300ms. (Fig.3). Figure 3 presents a replacement scheme on which the mathematical model of the measuring chamber is based, representing the simplified model of heat exchange, for which in its operation and, accordingly, in the calculations, the following are also taken into account: the power dissipated in the environment - Penv, the heat capacity of the heater - Ch, as well as the heat capacity of the sample in the chamber - Cs;

[0020] Figure 4 shows the time diagram of the temperature changing of the heater and the sample in the measuring chamber.

[0021] For three or more set sample temperatures Tsl, Ts2, Ts3 Tsn, the corresponding values of the ultrasound velocity (Vusl, Vus2, Vus3,... Vusn) are determined. The energy consumed for heating the sample from the first set temperature Tsl to the last set temperature Tsn is obtained after integrating the power dissipated by the heater for the corresponding time interval:ET M=J P(t).dt

[0022]

[0023] The control module, through the obtained specific values of the ultrasound speed Vusl, Vus2, Vus3,... Vusn and the energy released by the heater Eln - for heating the sample, determines the desired parameters of the sample - for example, milk fat content - Fat, the content of dry non-fat residue of milk - SNF and the protein milk content - Prot; (Fig. 2); The figure visualizes the last five consecutive actions, marked in Fig. 2 as Bl, B2, B3, B4 and B5, describing the method for determining milk quality.

[0024] The task of the invention is solved by a device for determining the milk quality (Fig. 1), which is built of a measuring unit, a control unit and a feed hopper connected to each other.

[0025] The measuring unit consists of a measuring chamber, equipped with a heater, and the inlet of this chamber is connected to the feed hopper by pipelines. At its other end - at the outlet, the measuring chamber is connected by pipeline to an expansion tank and a pump. At both ends of the measuring chamber are located an ultrasound emitter and an ultrasound receiver.

[0026] The control unit is built of a control module and a power supply module, connected to each other. The power supply module is connected in an electrical power loop with a switch, a heater, and a current sensor, successively connected to it.

[0027] The control module, in turn, is connected to the elements of the measuring unit, and in particular - is connected bidirectionally to the pump, to the current sensor and is connected through the switch to the heater. The control module is also connected in an electrical loop with the ultrasound emitter and the ultrasound receiver. A shunt resistor can be used as a current sensor, the voltage drop from which enters the control module. At both ends of the heater, points for measuringthe voltage Uh are provided, namely KI and K2, which are also connected to the control module.

[0028] The power supply module powers the heater and the control module, through which the pump, the emitter and the ultrasound receiver are also powered. The power supply module is successively connected to the switch, the heater and a current sensor, and the current sensor is also connected to the control module, which receives from it a signal for the current strength Ih of the heater.

[0029] The advantages of the device and method consist in measuring the ultrasound velocity at three or more temperatures, without waiting for each temperature to be established, and heating is performed with a constantly switched on heater until the set final temperature is reached, as the sample temperature is calculated indirectly from the measured temperature and heater power. An additional advantage is the accounting of the energy consumed for heating the sample, which is related to the heat capacity of the sample. Thus a rich set of data in a short time is achieved, using a simple and inexpensive device. The rich set of measured data provides the opportunity to obtain precise measurements of more sample parameters, such as milk fat values Fat, milk solids content - SNF and milk protein content Prot;

[0030] BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Fig. 1 shows a device for determining the fat content and dry non-fat residue, according to the invention.

[0032] Fig. 2 shows the method and the sequence of processing the measured data, according to the invention;

[0033] Fig. 3 shows the replacement scheme, on which the mathematical model of the measuring chamber is based;

[0034] Fig. 4 shows a time diagram of temperature changing of the heater and of the sample in the measuring chamber, during the heating period.

[0035] EMBODIMENT OF THE INVENTION

[0036] A method and a device for determining the milk quality have been created,consisting of a measuring unit 1, a control unit 2, and a feed hopper 13, connected to each other. The measuring unit 1 consists of a measuring chamber 3, equipped with a heater 4 and connected at the inlet to the feed hopper 13 via a pipeline 13.1. At its other end - the outlet, the measuring chamber 3 is connected via a pipeline 13.2 to an expansion tank 9 and a pump 8. At both ends of the measuring chamber 3 are located an ultrasound emitter 5 and an ultrasound receiver 6.

[0037] The control unit 2 contains a power supply module 11, which supplies heater 4 and control module 10, through which in turn the elements of the measuring unit 1 are also supplied, and in particular - the pump 8, the emitter 5 and the ultrasound receiver 6. The electrical circuit of heater 4 includes a power supply module 11, a switch 12 and a current sensor 7. A shunt resistor is used as a current sensor, the voltage drop from which enters the control module 10. At both ends of heater 4, voltage measurement points Uh - KI and K2 are provided, also connected to control module 10.

[0038] In general, the control unit consists of an interconnected control module 10, a power supply module 11 and a semiconductor switch 12. The control module 10 is connected to an ultrasound emitter 5, an ultrasound receiver 6, and a semiconductor switch 12, a current sensor 7 and the voltage measurement points at both ends of the heater. The control module 10 is connected bidirectionally to a pump 8.

[0039] The device operates as follows: By pump 8, the milk is sucked from the feed hopper 13, which fills the chamber 3 and part of the expansion tank 9. The heater 4 is powered by switch 12 and remains constantly on until the sample is heated to the set final heating temperature of 62° C. During heating, every 80ms the control module 10 measures the voltage Uh and the current Ih of heater 4 and the speed of the ultrasound Vus passing through the sample. The corresponding power Ph, resistance Rh and heater temperature Th are calculated during the entire heating period for each report of voltage and current of the heater. Using a simplified computer model of the process, the control module 10 determines the sampletemperature Ts, and when temperatures 44°C, 53°C and 62°C are reached, the measuring module 10 reads and stores the ultrasound speeds - Vus1, Vus2 и Vus3, corresponding to these temperatures.

[0040] In the time interval from reaching the sample temperature of 44°C to reaching 62°C, the measuring module 10 integrates the heater power to calculate the energy consumed by the heater for heating the sample from 44°C to 62°C. After reaching the set final heating temperature of 62°C, the control module 10 turns off the heater 4, using the switch 12.

[0041] Then, the control module 10, using the obtained values for the ultrasound speed Vusl, 2, 3 and the energy released by the heater Eln - for heating the sample from 44°C to 62°C, determines the milk fat content Fat, the content of dry non-fat residue in the milk - SNF and the protein content in the milk Prot. Fig. 3 shows the replacement scheme on which the mathematical model of the measuring chamber is based;

[0042] APPLICATION OF THE INVENTION

[0043] The invention is used in measurements at milk reception points, milk processing plants, measurements by control bodies for the qualities of milk used in products. The invention is used in dairy farms, for establishing the initial parameters of the milk produced.

[0044] The invention is used in monitoring and controlling the health of herds, with the opportunity of feedback, indicating prescribed veterinary measures - prescribing feeding recipes, treatment with medications, etc., in dairy farms, to establish the initial parameters of the milk produced.

[0045] Literature:

[0046] 1. Patent BG 64468 B1;

[0047] 2. Patent application BG110521 Al;

Claims

CLAIMSofA METHOD AND DEVICE, DETERMINING THE MILK QUALITY l. Method for determining the milk quality, which consists of suctioning from a feed hopper of the measured food fluid, and transporting it into a measuring chamber equipped with a heater, filling the chamber, together with a part of an expansion tank, through a pump, in amount representing a test sample, heating this test sample, and at the same time, through the heated sample, ultrasound is emitted, measuring its propagation speed, corresponding to the temperature, characterized in that the measured sample is heated to a final temperature in the range from 60°C to 64°C, with continuous and uniform heating, as during the heating period from its beginning, until reaching the final heating temperature - a temperature in the range from 60°C to 64°C, during the entire heating period, the control module (10) measures and records the voltage of the heater (4) - Uh, and a current sensor measures and reports (7) the current strength Ih of the heater (4), as well as simultaneously with the measured voltage - Uh and the current strength Ih of the heater, the ultrasound emitted from the ultrasound emitter (5), to the ultrasound receiver (6), is also measured in parallel and the ultrasound speed - Vus is recorded, as during the heating period, the measurement is a continuous process but in intervals of 30μs to 300ms, as the control module (10), after recording the values of the voltage Uh and the current strength Ih of the heater (4), for each of the intervals from 30μs to 300ms in function of each of the measured values of the voltage Uh and current Ih of the heater (4), for each measured interval, the corresponding power Ph and the corresponding resistance Rh of the heater (4) are calculated, and at the same time, the temperature of the heater (4) - Th is determined by the resistance of the heater Rh, then, using the found heater temperature Th, the sample temperature - Ts is determined, as the sample analysis during the heating period -from 60°C to 64°C is performed for at least three or more preset sampletemperatures Ts1 Ts2 Ts3….. Tsn , and when these temperature values are reached in the heating process, the corresponding ultrasound velocity values are determined (Vusl, Vus2, Vus3,... Vusn) and the energy - Eln, released by the heater (4) for heating the sample, from the moment of reaching the first set temperature Tsl is calculated, until the last set temperature Tsn is reached, as the control module (10), from obtained values of the ultrasound speed Vus(l n) and energy released by the heater Eln - for heating the sample, determines the milk fat content Fat, the content of dry non-fat milk residue - SNF and the protein content in the milk Prof;2. A device for determining the milk quality, which is made up of a measuring unit and a control unit, connected to each other, as the measuring unit is connected to a supply hopper, via a pipeline equipped with a preheating unit, as the measuring unit contains a measuring chamber, equipped with a heater, and at both ends of the measuring chamber an ultrasound emitter and receiver are located, and at its outlet, the measuring chamber is connected via a pipeline to an expansion tank and a pump, characterized in that the control unit (2) consists of a control module (10) and a power module (11), connected to each other, as the control module (10) is bidirectionally connected to a pump (8), to a current sensor (7) and connected via a switch (12) to a heater (4), and control points KI and K2, as the control module (10) is further connected in an electrical circuit to the ultrasound emitter (5) and the ultrasound receiver (6), and the power module (11) is connected in an electrical power circuit, which includes the interconnected switches (12), heater (4), and current sensor (7), all of them connected to each other;3. A device for determining the milk quality, according to claim 2, characterized in that a shunt resistor is used as the current sensor (7);4. A device for determining the milk quality, according to claim 2, characterized in that a semiconductor switch is used as the switch (12);

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