SU1642240A1 - Method and apparatus for metering the flow of green fodder - Google Patents

Abstract

The invention relates to a control technique and can be used in agricultural feed preparation to measure the consumption of chopped juicy green fodder in a continuous stream. The purpose of the invention is to improve accuracy. The feed stream is irradiated perpendicularly to its surface by microwave radiation of the first frequency and at an acute angle to the surface of the stream by microwave radiation of a second frequency greater than the first. The attenuation of the transmitted power and the reflected microwave power of the first frequency are recorded, the reflected and scattered power of the microwave radiation of the second frequency is recorded, and the pre-Cohr shift of the reflected radiation is determined. The electronic circuit of the device in analog form, based on the measured values, determines the flow rate of the feed. 1 il. Yo

Description

The invention relates to a control and measurement technique and can be used in agricultural feed preparation for measuring the consumption of chopped juicy green fodder in a continuous stream.

The aim of the invention is to improve accuracy.

The essence of the method is that when probing shredded juicy-green feed with electromagnetic microwave waves, the effect of changes in the chemical composition of the feed and the parameters of the air filling the measuring channel on the flow measurement accuracy is significantly reduced. This is physically due to the prevalence in the microwave range of electromagnetic waves of dielectric losses in moisture over all other types of losses due to the prevalence in the frequency range of relaxation losses associated with the polarization of water molecules. Thus, the attenuation of the radiated power of electromagnetic microwave waves in crushed juicy green The food is determined mainly by moisture.

The radiated power of the electromagnetic microwave waves is distributed as follows:

ABOUT

Ј

TO)

Yu

4 o

Po Pi + Pz + РЗ + Рч.

(one)

where PO, PL P2. Рз, Р4 - respectively, the power of the emitted, reflected, scattered, -absorbed and transmitted waves.

The power loss for dispersion can be neglected when the Rele criterion is satisfied; if a

T5yt- (2)

where h is the largest particle size of the controlled flow;

, I is the length of the probe wave electromagnetic wave;

a is the angle of sounding of the flow (acute angle between the direction of flow and the direction of sounding), Pr 0.

In the long wavelength part of the microwave range, this condition is fulfilled for all streams of crushed juicy green fodder in a suspended state in free space. Measured radiated Po, reflected Pi and passed P2 power normally irradiating the flow of microwave waves, determine the portion of power absorbed by Pz chopped feed

P3 Po-Pl-P /) f (Mi), (3)

thus, regardless of the chemical composition of the feed and the air parameters, and the mass Mi contained in the estimated volume of the feed flow of moisture. The moisture mass is calculated from the attenuation of the radiated power in the feed stream Na

Po-pi

P4

 f (N3),

(four)

where Ki is a conversion factor that does not depend on the controlled feed.

To eliminate the influence on the measurements of the ratio of moisture and dry matter in the feed, its moisture content W is additionally determined. Then the mass of feed Mo in the estimated volume can be calculated from the ratio

Mi

Mo:

W

(five)

regardless of the quality and type of juicy green food.

The reflectivity of a surface is primarily due to its moisture, density and roughness. Therefore, to measure the moisture content of the feed using the reflected power method is necessary .-

It is possible to introduce a correction in the density and roughness of the irradiated flux surface. The separation of the useful and interfering signals is carried out both according to the frequencies of the microwave radiation - to compensate for the change. -

flow density, and the angles of sounding the flow - to compensate for changes in the roughness of the reflecting surface. In this case, one frequency is selected in the region of the highest sensitivity to moisture and the lowest to density and roughness, while the other frequency is taken from opposite conditions. The sensitivity of the reflection method for measuring humidity increases with increasing wavelength of the probing microwave radiation, therefore, to obtain information on feed moisture, the change in the reflected power of the long-wavelength normally probing flux of microwave radiation is used, which also changes to determine the power absorbed in the feed. When monitoring the feed flux density, the sensitivity of the reflection method increases with increasing frequency of the microwave radiation, so the second frequency is selected in the short-wave part of the microwave range. The surface roughness is one of the main factors determining the ratio of the specularly reflected and diffusely scattered energy of microwave radiation, directed at an acute angle to the surface. If the height of the inequalities on the entire surface satisfies the condition

I

h

16 sina

(6)

then, by the reverse reflection of the microwave radiation, which probes the feed stream at an angle, one can judge the degree of roughness of the reflecting surface. For this, the feed stream is probed at an acute angle of the second microwave radiation. The feed moisture is then determined from the difference in the return power loss of the first and second frequency emissions using a calibration curve, regardless of the reflective surface roughness and flux density. Measuring the Doppler frequency fg of the reflected wave relative to the microwave radiation flux incident during sounding at an acute angle to the direction of motion and the sign of the radiated wavelength I and the sounding angle of the flux a, determine the flow velocity v by the formula

50 55

v 2 cos a fg

(7)

According to the information received on the mass of Mo feed in the estimated volume and flow velocity v, the flow of ground juicy green feed Qp in a continuous stream is determined.

Qp To MOV,

(eight)

where K is a conversion factor constant for a given measuring channel.

The drawing shows the functional diagram of the device for carrying out the proposed method.

The device consists of the first microwave generator 1, the first power allocation unit 2, the power divider 3, the voltage divider 4, the subtraction unit 5, the first reflected power recording unit 6, the second reflected power recording unit 7, the first antenna 8, the second antenna 9, the third antenna 10, the fourth antenna 11, the first logarithmic amplifier 12, the controlled differential amplifier 13, the second logarithmic amplifier 14, the second microwave generator 15, the double tee 16, the second power allocation unit 17, the third unit 18 audio power mixer 19, first amplifier 20, the converter 21, controlled integrator 22, the detector 23, the second amplifier 24, a third logarithmic differential amplifier 25, the divider 26 and the multiplier 27.

The device works as follows

The electromagnetic microwave radiation of the first part is supplied from the first microwave generator 1 through the first power allocation unit 2 to the power splitter 3. In this case, in the power allocation unit, an electrical signal Io is formed at a selected scale, proportional to the microwave power radiated by the generator 1, in the power divider 3, the radiated power is distributed in a 2: 1 ratio between the two arms, from which, respectively, through the blocks 6 and 7, the reflected power is emitted to the controlled stream 28 normal to the direction of its movement by receiving and transmitting antennas 8 and 10. The radiation from antenna 8 is linearly polarized in the horizontal plane, and from antenna 10 in the vertical plane . In this case, in the blocks 6 and 7 of the registration of the reflected power, the electrical signals ui and u are formed, respectively, proportional to the back-reflected microwave power and the first-frequency emissions. Moreover, in block 6, an electrical signal ui is generated, which carries information about the reflective properties of the entire feed stream, and in block 7, an electrical signal ui, depending on

reflective properties stable in size. flow surface frames.

Thus, part of the radiated microwave power of the first frequency is reflected from the feed stream 28 and recorded by blocks 6 and 7, and the other part of the power of the microwave radiation linearly polarized in the horizontal plane after being attenuated in the feed stream is recorded through the receiving antenna 9

detector 23. The transmitted part of the microwave power, linearly polarized in the vertical plane, is not perceived by the antenna 9, due to different polarization, the second amplifier

24 generates, at a selected scale, an electrical signal proportional to the transmitted power.

At the same time, the feed stream is probed at an acute angle by the radiation of the second

frequencies from the second microwave generator 15. A double tee 16 serves to untie the receiving and transmitting paths and to communicate the mixer 19c with the microwave generator 15. The radiated power passes through the glare 17 and

18, the power output is radiated by the antenna 11 to the feed stream. Through the same antenna, a portion of the microwave radiation reflected from a dimensionally stable flow surface is received, which passes through blocks 17

and 28 and a double tee 16 to the mixer 19. In this case, in the power allocation unit 17, an electrical signal io is generated, proportional to the power radiated by the microwave generator 15, and in unit 18, an electrical signal ui1, proportional to the power reflected from the flow. The mixer 19 through the double tee 16 also receives a portion of the radiated power from the generator 15. It produces

the Doppler frequency signal, which is amplified by the first amplifier 20, is then generated in a converter 21 into a pulse train with the Doppler frequency fg and averaged by the controlled integrator 22. In the latter, a signal uv is generated that is proportional to the speed of the flow. At the same time, by applying the control signal to the integrator 22 from the third logarithmic differential amplifier 25, the averaging time changes depending on the changes in the flow rate. In the voltage divider 4, the input of which receives an electrical signal about the radiated power of microwave radiation, electrical signals Io and Io are generated at the first frequency, which are respectively proportional to the radiated power through the first and second outputs of power divider 3.

In block 5, the subtraction is determined by the difference of the signals (uo1 -ui1), which is fed to the first input of the third logarithmic differential amplifier 25, to the second input of which the second amplifier 24 receives the signal uV. At the output of the third logarithmic differential amplifier 25, a signal is generated that is proportional to the attenuation of the radiation power transmitted through the normal to the flow

N3 10 Ig

but - w

U4

In the first logarithmic differential amplifier 12, the outputs of which receive signals from the voltage divider 4 and the second reflected power recording unit 7, determine the reflected microwave power of the first frequency from a stable stream surface

There is a signal on the mass of Mo feed in the estimated flow volume

u mo

 N3

l Mobr

The feed mass signals in the estimated flow volume and MO and the flow velocity uv are multiplied in multiplier 27, at the output of which an electrical signal UQ is formed, which is proportional to the flow of the ground juicy green feed and does not depend on its type, i.e.

u Q and MO uv

Thus, the inventive device makes it possible to measure the flow rate of chopped juicy green fodder in a continuous stream. Accuracy is increased by eliminating the dependence of the measurement result on the chemical composition and moisture content of the feed.

N06p.i Yu Ig

up

U1

In the second logarithmic differential amplifier 14, the inputs of which receive signals IO1 and, respectively, from power allocation blocks 17 and 18, the return loss of microwave radiation of the second frequency from the same dimensionally stable flow surface as in the case of determining N06p 1 is determined, t .

uo

N06p.2 10 Ig -yjj.

Then, in the controlled differential amplifier 13, by its inputs connected with the first and second logarithmic differential amplifiers 12 and 14, the difference of the return loss of the first and second frequencies is determined.

DMobr Mobr 1 Mobr 2 At the same time, the control input of the amplifier 13 receives a signal from the logarithmic differential amplifier 25 proportional to the thickness of the flow in the direction of sounding. As a result, the effect of varying the thickness of the flow on its reflective properties is compensated.

The divider 26 receives signals Мз and ДМобр, which are proportional, respectively, to the mass, moisture contained in the feed Mi and feed moisture W. and at its output form 5

0

five

0

0

Claims (2)

1. A method for measuring the flow rate of crushed juicy-green fodder, which consists in determining the flow velocity and the mass of the material in the estimated volume by measuring the attenuation of the power of the probe radiation tray, characterized in that, in order to improve the accuracy, electromagnetic pulses are used as the probing radiation flux. 5 The microwave waves of the first and second frequencies, which irradiate the flow of the crushed feed at the exit of the feeder in free space, respectively, normal and at an angle to the direction of flow, determine the attenuation of the power of the normalized radiation in the feed stream and judge the mass the moisture contained in it simultaneously determines the magnitude of the reflected power of the radiation of the first and second frequencies and the Doppler frequency shift of the radiation directed at an acute angle, judging by the magnitude of the power of the moisture content of the feed, and Rovsky shift is judged on the flow rate, after which the obtained data rate is determined crushed lush green fodder. 2. A device for measuring the flow rate of chopped juicy-green fodder, containing the first microwave generator, the second 5 microwave generator, first and second antennas located on the same axis on opposite sides of the stream, third and fourth antennas located in the same plane successively along the controlled flow, a mixer, a divider and a multiplier, characterized in that, in order to improve accuracy, it is equipped with a double tee, a power divider, a voltage divider, the first, second and third power allocation units, the first and second reflected power recording units, the first and second amplifiers controlled by the integrator, the first, second and third logarithmic differential amplifiers, the subtraction unit and the detector, the first microwave generator connected to the first power allocation unit and the power splitter, the first output of which is connected to the first antenna, and the second output through the second recording unit of the reflected power — with the third antenna, and the output of the first Power allocation unit is connected to the input the voltage voltage, the first output of which is connected to the first input of the subtraction unit, and the second output - to the first input of the first logarithmic differential amplifier; the second input of the subtraction unit is connected to the output of the first reflection power register, the second input of the first logarithmic differential amplifier - to the output the second unit for recording the reflected power, and the output of the first logarithmic differential amplifier is connected to the first input of the differential controlled the amplifier whose second input is connected to the output of the second logarithmic differential amplifier, and the control input to the output of the third logarithmic differential amplifier, wherein the first and second inputs of the second logarithmic differential amplifier are respectively connected to the outputs of the second and third power allocation units, which are connected in series with the fourth antenna and through a double tee to a second microwave generator, while the second output of the double tee is connected through a mixer by series-connected second amplifier, transducer and integrator controlled, the output of which is connected to the first input of the multiplier, while the control input the integrator is connected to the output of the third logarithmic amplifier, and the second input of the multiplier is connected to the output of the divider, the first input of which is connected to the output of the differential controlled amplifier, and the second input is with the output of the third logarithmic differential amplifier, the first input of which is connected to the output of the first amplifier, and the second input is the output of the subtractor, while the second antenna and the first antenna are linearly polarized in a horizontal plane and directed perpendicular to the first amplifier straight to the flow, a third antenna is also directed linearly polarized in the vertical plane, and The fourth antenna is directed at an acute angle to the flow. 0 /four 15 sixteen 17 18 Jl nineteen 20 - 21 K s J 26 22 27 ttt