SU1612259A1 - Method and apparatus for determining fraction of total mass of fat and dry defatted residue in milk - Google Patents

Abstract

The invention relates to the dairy industry, namely to the analysis of raw materials and products. The purpose of the invention is to reduce the time and increase the accuracy by fixing the moment of temperature equalization on the surface of the measuring cell and in the test milk sample. The test sample is placed in a measuring chamber, heated to 41 ° C, the ultrasound velocity is measured at the time points at which the increment of the ultrasound propagation velocity in milk equals a predetermined value of 10 kHz / s. Then, it is heated to 65 ° C on the surface of the measuring chamber and the ultrasound velocity is again measured at the time points at which the increment of the ultrasound propagation velocity in the milk equals the set value — 10 kHz / s. The weight fractions of the fat and dry skim residue are determined by known formulas in which the measured values of the ultrasound velocities are used. The coefficients of the measured values and the free terms of the equations are determined from the results of the calibration. 2 sec. f-ly, 3 ill.

Description

the distribution of ultrasound in milk is equal to a given value.

For carrying out the method, a device comprising a measuring cell, an ultrasound source and receiver, a heating element, a temperature sensor, a processing and control unit is additionally equipped with an auto-circulation unit, connected in series with a voltage source, a key, a reference element, a current amplifier, the output of which is through the heating the element is connected to the measuring cell, with the first and second outputs of the autocirculation block being connected respectively to the output of the ultrasound source and ne the second input of the processing and control unit, the second input of which is connected to the output of the comparison element, the second input of which is connected to the output of the temperature sensor located on the surface of the measuring cell, while the first and second outputs of the processing and control unit are connected respectively to the control input of the key and the second input of the auto-circulation unit, the first input of which is connected to the output of the ultrasound receiver.

Monitoring the moment when the test sample reaches each of the two specified temperature values by incrementing the speed of ultrasound with a resolution of 5-10 seconds over a time interval during which the temperature on the surface of the measuring cell is equal to the temperature of the milk sample in the measuring cell, and measuring the speed of ultrasound in milk when the increment of ultrasound speed in milk of a given value is achieved, an unambiguous determination of the milk sample and the corresponding unambiguous value are provided the value of the ultrasound velocity in the sample, which makes it possible to increase the measurement accuracy without decreasing the productivity.

Fig. 1 shows the zone of possible values of the time dependence and the change in the speed of ultrasound propagation in the sample when the temperatures on the surface of the measuring chamber and in the milk sample are equal to one temperature, for example T1 41 ° C; in fig. 2 - block diagram of the device that implements the method; in fig. 3 - a simplified algorithm for the operation of the device.

The method is carried out as follows.

The milk sample is placed in the measuring cell, heated to the first temperature value, for example, the temperature on the surface of the measuring chamber 41 ° C (Fig. 3), and then control of the ultrasonic velocity increment in the sample is started. Determination of ultrasound velocity in the sample

carried out by measuring the pulse frequency, varying in proportion to the speed of propagation of ultrasound. Upon reaching the increment of the pulse frequency specified

0 value Л F 10 Hz / s, which corresponds to the moment when the test sample reaches the first specified temperature value, and its leveling in the test sample and on the cell surface is fixed

5 Fi frequencies. Next, the milk sample is heated to a temperature value on the surface of the measuring chamber equal to 65 ° C, and when the increment of the pulse frequency is reached, the specified AF value

0 10 Hz / s fix the value of the frequency P2. Using the results of both measurements of the frequencies FI and F2, using the data of preliminary calibration, the mass fractions of fat and dry skim residue in the sample are calculated.

5 according to the formulas

Cx Fl XKi -) - F2X K2 + KZ; (1)

Ссо Fi X К4 + F2 X Kb + Kb. (2)

where Сж and Ссо are the mass fractions of fat and dry skimmed residue, respectively;

0 Ki-Ke are empirical coefficients determined during calibration;

FI, F2 are the values of the pulse frequency, respectively, at temperatures of 41 and 65 ° C, measured at time points,

5 at which the increment of the pulse frequency reaches the specified value of A.F.

The set value of the pulse frequency increment A F is determined by

0 experimentally. For this reason, the time dependence of the ultrasound velocity change in the measuring chamber is removed in the time interval from the moment of reaching a certain temperature.

5 (for example, 41 ° C) on the surface of the measuring chamber to warm the milk sample in the measuring chamber to the same temperature (figure 1). From the dependence shown in Fig. 1, it can be seen that the measurement process is about

The ultrasonic growth rate in the measuring chamber is exponential, therefore, to shorten the measurement time and to unambiguously determine the temperature in the milk sample, the process is limited in time and

55 analyze the obtained dependence in the time interval during which the increment of the ultrasound velocity in the milk sample is 90% of the increment of the ultrasound velocity corresponding to the determination of the temperature on the surface of the measuring chamber in n}) o5e milk. The analysis of the obtained dependence is carried out through equal time intervals with discreteness, for example, by comparing the ultrasound velocity increment in the previous interval with the ultrasound velocity increment in the subsequent interval. When the ultrasonic velocity increment reaches a predetermined value, the analysis is terminated — and is restarted. The value of the velocity of the velocity in the measuring cell is measured. The set value of the ultrasound velocity increment (increment of the pulse repetition rate) in the analyzed time interval and the duration of equal time intervals are determined by the required measurement accuracy.

A device that implements spdbd (fg.2) contains a 1 measuring cell 1, at the ends of which the source 2 and 2 are located. 3 ultrasound receiver. On the surface of the measuring cell 1 there is a temperature sensor 4 and. a heating element . In addition, the device contains an autocirculation unit b, a source 7 of reference outputs, a key 8, an element 9 of a transmitter, a current amplifier 10, a processing and control unit 11 containing an indicator 12, ports 13 Input / Output, address register 14 (RA), r.egistr 15 of control (RU), arithmetic logic converter (A / 1P) 16. operational memory element (OZE) 17, permanent memory. element (PZE) 18. The first output of the truck is ku-. of the control unit 6 is connected ((with the input of the ultrasound source 2, the second output of the autocirculation unit 6 is connected to; the first input of the processing and control unit 11; the outputs of the source of the reference voltages through the corresponding inputs of the connector 8 alternately connect one of the arcs of element 9 is a slow-moving one, to the other input of which is the output of the sensor output of temperature 4. tours. The output of element 9 of the relay is connected to the second input of block 11 o: operating i-controller: rle.il or input of usl. 10current .a1- stroke of which is connected to the input of the heating element 5. Control Key 8 is connected to the first output of the processing unit 11 and the control. The second output of which is connected to the same input of the circulation unit 6 of the block 6, the input of which is connected to the output of the receiver 3 of ultrasound. li.o.6pa and processing are parallel to each other by a data bus and control and addressing. At that, W-ROUTS. ALP 1-6 is connected to s.otsotstow: Yu1DI and ohoda.mi

FA 14 and RU 15, and one of the outputs of the ports 13 is connected to the input of the indicator 12, the other inputs and outputs of the ports 13 are connected respectively to the output of the control element 9, the control input of the key 8, one of the outputs and one of the inputs of the auto-circulation unit 6

Perhaps a different specific implementation of the blocks included in the device

implementing method. Below is one of the possible options for the implementation of blocks.

The measuring cell 1 is made in the form of a thin-walled metal tube with

good thermal conductivity, such as copper. Source 2 and ultrasound receiver 3 are made of piezo-ceramics. The heating element 5 is a resistive heating element in the form of a single-layer winding. The temperature sensor 4 is made in the form of six series-connected silicon diodes included in forward bias. Auto circulation block 6 is made according to the generator circuit with

external acoustic communication, in which the measuring cell 1 is used. The source of 7 reference voltages is made using an integrated precision voltage regulator,

key 8 - using the chip.

Element9sraoneni is made on: a base of an operation amplifier. Current amplifier 10

made using transistors

high power.

Block 11 of processing and control is performed on the basis of a microprocessor set that implements the functions of calculating according to a given formula AND controlling the generation of key switch signals (heating the sample to 41 to 65 ° C) and starting the autocirculation unit 6 at the necessary time points. Preparation of the block 11 o.br.ab.otki and management to work.

. In the permanent storage element

PZE 18-unit 11 processing and control

enter the values of the coefficients KI ... KB

(formulas (1),. (12), preliminarily determined experimentally at the device calibration, and the value of the ultrasound velocity increment, at which Topor i will record the values of the speed of ultrasound. The PZE 18 also introduces a rogram of operation of the device, The algorithm is coordinated in Fig. 3.

A milk sample is introduced into. measuring cell 1. include the device to measure. The operation of the device occurs according to the program recorded on LZE 1: 8 according to an algorithm brought in FIG. 3 ..

Stage 1 (device start). When the start signal is received, the initial setting of the address and control registers 14 and 15 to the zero state is carried out. In the future, in PA 14 and in RU15, the number code corresponding to the device address code and the control signal code will be rewritten from LSA 16. The initial address code and the control signal code are transmitted via the control bus and addresses to the corresponding inputs of the EE 18.

Stage 2 (FIG. 3). From the output of PZE 18, the command entered in the initial address of the PZE 18 is sent to the LSA 16 via the data bus. The LSA 16 generates and overwrites the control signal codes and addresses to the I / O ports 13 on the RU 15 and RA-14. one of. ports, the control signal switches key 8 to the first position corresponding to a temperature of 41 ° C.

Stage 3 (heating of the sample to a value of 41 ° C). When switching the key 8 to the first position, the voltage Ui is supplied from the output of the source 7 of the reference voltages to one of the inputs of the reference element 9, corresponding to the voltage of the output of the sensor A to the temperature at temperature. the surface of the measuring cell equal to 41 ° C. The other input of the comparison element 9 is supplied with a voltage from the output of the temperature sensor 4, which, when a milk sample is introduced into measuring cell 1, differs from the voltage at the first input of the comparison element 9, since the temperature of the sample and, therefore, the sensor temperature is below 41 ° C . At the output of the comparison element 9, a difference signal is formed, which through the current amplifier 10 is fed to the heating element 5. The heating occurs in the measuring cell 1; When the temperature on the surface of the measuring chamber is reached, the voltage from the source 7 of the reference voltages supplied to the first input of the reference element 9 and the voltage from the output of the temperature sensor 4 to the second input of the comparison element 9 becomes equal to In comparison, a zero difference signal is generated and the measurement cell is discontinued. When the temperature on the surface of the cell 1 and the output of the comparison element 9 is lowered, the difference signal that goes through the body 10 enters the heating element 5 and thus the temperature is maintained at. the surface of the measuring chamber 41 ° G. When the temperature on the surface of the measuring cell 1 is reached, the zero difference signal from the output of the comparison element 9 through one of the inputs of port 13 I / O and the data bus enters the LSA 16 and is perceived as. signal to reach the required temperature

on the surface of the measuring cell. ALP. 16 forms and rewrites in RA 14 and RU 15. the corresponding codes, on which at one of the outputs of the ports 13 I / O the impulse is formed, which enters

one of the passes of the autocirculation unit 6, where it amplifies in amplitude to a value of 50 V, is normalized to a duration of 100 NS and enters the ultrasound source 2, In ultrasound source 2

the electrical signal is converted to ultrasound, which, having passed through a milk sample after 70 μs in a measuring chamber approximately 100 mm long, is converted again into an electrical signal in receiver 3, and comes to one of the inputs of the autocirculation unit 6, since blocks 6, 2, 1, 3 are interconnected. Thus, at the output of the autocirculation unit 6, a continuous sequence of pulses is formed, whose frequency (F) is determined by the speed of ultrasound propagation in milk. At the same time, the LSA 15 generates and rewrites the following address and control values in RA 14 and RU 15, according to which the next command is received from PZE 18 and the frequency increment analysis is started ..

Etchp 4 (analysis increment frequency A F). Since the heating element is located on the surface of a measuring cell made of thin-walled material with good thermal conductivity, heating and thermal stabilization of the temperature of the measuring cell 1 occurs DO cremoni quickly. The temperature of the milk sample is heated and thermally stabilized somewhat medically. Therefore, when the temperature on the surface of the measuring cell 1 is stabilized, the sample temperature

some time is changed, which leads to a change in the pulse frequency from the output of the circulatory unit 6. The analysis of the increment in the frequency of the signal is as follows. From the output of the VCT,

the cooking unit 6 pulses through one of the inputs of ports 13 I / O and the data bus arrive at ALP 16, where they are processed. ALP 16, RA 14 are involved in processing. 15, OZE 17, PZE 18.

The processing is carried out; in

the program recorded in the SCE as follows

way: - ...

1. Oschischtvl etc count the number of pulses with a given discreteness of p-s with).

The pulse number code is recorded in the first cell of the SEM.

. 2. The number of pulses is recounted over the same interval and the number code is overwritten in the second cell of RAM:

3. In ALP 16, subtraction is performed. previous number of pulses from the next, located in the corresponding cells of OZE IT, Number code corresponding to the difference of the first and second numbers, t, e. frequency increment is recorded in the third cell of the OZE 17 ..

4. In ALP 16, the code of the number of the third cell of the OZE 17 is compared with the code of the number of the defined cell of the EEED.18, in which the code of the number of the required increment ..,.

5. If the frequency increment does not match the required value of 1o, the operations on nnil-A are repeated.

Stage 5 (write Fi). If the frequency increment is equal to -tree & the desired value, then the code of the number corresponding to the last value of the frequency record (the value of the pulse frequency in the Circle of a block) is rewritten into the fourth cell of the OZE 17 ,. ALL 16 forms and overwrites in RA. 14 and RU 15 codes, according to which they are: PZE 18- enters / command at the level of the next step of the algorithm.

Stage G (turning on the heater in T2 mode). The operation of the device is carried out - similar to step 2, but the key 8 is switched to the BQBTQpoe position. .

: Stage 7 (heated sample. To 65 ° C). The operation of the device is carried out analogously. Manually to the stage: 3, but the key 8 is in the second position: the heating and the staglV n lz l l l temperature shall be set to

, -.: -:. ; ... . ,;

Step 8 (frequency increment analysis D .F), the operation of the device is performed analogously to step 3,

Stage 9 (Record-Fa). The work is carried out at the same time as stage 5, but the rewriting of the code of the number (the value of the frequency of the pulses of the automatic backing unit) is performed in the fifth cell of the OZE 17 ..

Step 10 (calculation of the percentage of fat and CO MO). In this work: the ALP 16, RA 14, RU 15, OZE 17. units are functioning. The EZE 18.. The processing process is carried out according to the program recorded in the EZE 18 according to the above formulas. In the calculations, the values of FI and F2 are used, which are in the fourth and fifth of the cell OZ 17. and the coefficients Ki K2 ..... K6. KOTOpbix values are recorded in the corresponding cells of the PZE

18. The results of the calculation are recorded in the sixth and seventh cells of the OZE 17.

Stage 11 (indication). LSA Generates and overwrites codes in RA 14 and RU 15, according to which the results of calculations from the sixth and seventh cells of the OZE 17 through the data bus and one of the ports 13: Input / Output arrive at indicator 12.

Stage 12 (stop). In the LSA 16, the code of the number by which the device stops working according to the program is generated and 0 is overwritten in RU5. .

The proposed method and device for its implementation provide a more accurate, 5 than the known, proportional to the type of regulating / measuring temperature. The cells, due to a single warm-up of the sample and a rapid transition from one temperature to another, can reduce the time taken to measure one sample from 9Q s in a spirited device to 65 s in the proposed one and thus increase the productivity of the device by 1.38 times. The volume of the measuring device in a known device is 80 ml. 5 A significant advantage of the proposed technical solution is significantly less; milk consumption per measurement is 15 ml. Reducing the consumption of milk for one analysis of the proposed system gives a significant ekomomichichesky effect npv control the fat content in milk of dairy cows, which need to determine the fat content in milk in a 10-month periodontal period, 5 Hence, that the change of this technical solution only in this case gives the saving of milk 44000000X 10X (80- -15) 28600000 l, which at an average cost of 35 kP. for 1 l is about the money 40. expression 1C.01.00.00 rub.

Claims (2)

Claim 1. Sgresob. Olredele (and the mass fraction of fat and dry non-fat residue D milk, providing for heating a study of milk samples in the measuring cell, fixing the values of fast ultrasound at a given temperature by measuring the temperature the frequency of the pulse and the determination of the mass fraction of fat and dry degrease of the remainder of the system of two equations Cf ° FI .X Ki + F2 X .К2 + Кз; Ссо FI X К4 + F2 X К5 + Кб, .. where. Cf and Cs mass fraction of fat and dry; 55 skim residue, respectively; Kt - Kb - empirical coefficients. detectable during calibration; FI and F2 are the values of the ultrasound velocities of the co., Respectively, at -41 and 65 ° C. about t n and h a r p i and so. that, in order to reduce time and increase accuracy, they measure the time of temperature equalization on the surface of the measuring cell and in the milk sample under study when the temperature reaches the specified temperature values by measuring pulse frequency values with: 5–10 s resolution and setting increments of measured values, and The time of exponential temperature is recorded when an increase in the measured values of the pulse frequency of a given value is reached. 2. A device for determining the mass fraction of fat and dry skimmed milk residue, containing a measuring cell with a heating element, a temperature sensor / sources, an ultrasound receiver, a processing and control unit, so that to reduce time and increase accuracy, it is additionally equipped with an autocirculation unit and a series of reference voltage sources, a key, an element of comparison, and. the current amplifier connected to the heating element of the measuring cell, the first and second outputs of the autocirculation block are connected respectively to the input of the ultrasound sensor and the first input of the processing and control unit, the first and second inputs of which are connected to the control unit entrance; The key and the second input of the autocirculation unit are connected to the last input of the receiver: ultrasound. The temperature sensor is located on the surface of the measuring cell and connected to the second comparison output, the output of which is connected to the second input of the processing and control unit. chP111 11: n . SufdS tJjftSti 9ytscm% girao soma HH JKiKua (Stop) 4%