RU2508534C1 - Device for measurement of dielectric particle geometrical size - Google Patents

Abstract

FIELD: instrumentation.

SUBSTANCE: device for measurement of dielectric particle geometrical size comprises radiation source, detector and amplifier and, additionally, it incorporates circulator, horn receiving antenna, low-pass filter and microcontroller. Radiation source output is connected with circulator first arm. Circulator second arm is connected to transceiver horn antenna. Circulator third arm is connected to detector input. Detector output is connected via low-pass filter to amplifier input. Amplifier output is connected with microcontroller input.

EFFECT: higher precision.

1 dwg

Description

The invention relates to the field of measuring equipment and can be used in process control systems.

A photoelectric device for measuring particle sizes is known (see N.V. Krasnogorskaya, Yu.Ya. Kirilenko, M.M. Rybin. Investigation of the parameters of precipitation particles in a free atmosphere. Physics of the atmosphere and ocean, vol. 111, no. 12, p. 1292 -1304), containing a light source, mirror lenses, curtains for forming a light beam and a photomultiplier. In this device, the particle size is determined by the amplitude of the pulse arising on the anode of the photomultiplier when the light beam intersects the particle.

The disadvantage of this known device is the instability of the measurement results due to changes in the luminous flux of the light source.

The closest technical solution to the proposed one is the device adopted by the author for the prototype for measuring the size of a drop of water (see RF Patent No. 2393462). This device contains a pulse modulator, a radiation source connected to the output of the transmitting horn antenna, a receiving horn antenna, a detector connected by the output to the input of the amplifier, and an indicator. In this device, the output current of the detector is a function of the size of a drop of water.

The disadvantage of this device should be considered the error associated with the inconsistency of the area of the probe of the drop of water pulse with the area of the drop of water.

The technical result of the proposed solution is to increase the accuracy of measurement.

The technical result is achieved by the fact that a transceiver horn antenna, a circulator, a low-pass filter and a microcontroller are introduced into the device for measuring the geometric size of the dielectric particle, and the output of the radiation source 1 is connected to the first arm of the circulator, the second arm of which is connected to the transceiver horn antenna , the third arm of the circulator is connected to the input of the detector, the output of the detector through a low-pass filter is connected to the input of the amplifier, the output of which is connected to the input of the microcontroller.

The essence of the claimed invention, characterized by a combination of the above features, is that when probing a dielectric particle with an electromagnetic signal of a fixed frequency displayed on the display of the microcontroller, the size of the controlled particle is measured.

The presence in the inventive device of a combination of the listed existing features allows us to solve the problem of measuring the geometric particle size on the basis of a microcontroller that converts the analog information signal into digital with the desired technical solution, i.e. improving measurement accuracy.

The drawing shows a structural diagram of the device.

The device contains a radiation source 1, connected by an output to the first arm of the circulator 2, a transceiver horn antenna 3, a detector 4, a low-pass filter 5, an amplifier 6, connected by the output to the microcontroller 7. The number 8 denotes the dielectric particle.

The device operates as follows. The output electromagnetic continuous signal of a fixed frequency of the radiation source 1 is supplied to the first arm of the circulator 2. This signal is then transferred via the second arm of the circulator to the transceiver horn antenna 3, and then sent to the controlled dielectric spherical particle shape 8.

In the case under consideration, when this particle is irradiated with an electromagnetic signal and the condition d << λ is fulfilled, where d is the diameter of the spherical particle, λ is the electromagnetic wavelength, for the effective scattering (reflection) area of the particle, we can write (Mi formula)

$$\sigma ={\pi }^5{k}_m{d}^6/{\lambda }^{\mathrm{four}},\left(\mathrm{one}\right)$$

where σ is the effective scattering area of the particle;

, $$k_m=|\; |\; |m^2-\mathrm{one}/m^2+2|\; |\; |2$$

,

where m is the refractive index of the electromagnetic wave.

It can be seen from the above formula that, by estimating the parameter σ, one can determine the diameter (geometric size) of the irradiated particle.

For this, the signal scattered from the controlled particle is captured by the transceiver horn antenna and then, with the help of the third arm of the circulator, is fed to the input of detector 4 (see I.V. Lebedev. Microwave engineering and instruments. M .: Vysshaya shkola, 1970, p. 292 -293).

It is known that when receiving the signal reflected from the control object, the effective scattering area of the object can be expressed as:

$$\sigma =\mathrm{four}\pi r^2{P}_{\mathrm{about}tR}/P_{P\mathrm{but}d}.\left(2\right)$$

where r is the distance from the emitter to the object, P _Otr is the power flux density of the wave reflected from the object, P _pad is the power flux density of the wave incident on the object. Taking the last expression in relation to the case under consideration, we can state that a joint solution of (1) and (2) equations will make it possible to estimate the effective scattering area of a particle from the following formula:

. $$\pi \mathrm{four}{k}_m{d}^6/{\lambda }^{\mathrm{four}}=\mathrm{four}{r}^2{P}_{\mathrm{about}tR}/P_{P\mathrm{but}d}$$

.

From the last formula it can be seen that for known values of k _m , λ, P _pad and a constant distance between the controlled particle and the transceiver horn antenna (r) by measuring the power flux density of the wave (signal) reflected from the particle, one can judge the particle diameter. Due to this, the detector input signal corresponding to the power flux density of the wave reflected from the particle is first detected in the detector and then fed to the input of the low-pass filter 5 to suppress noise. The detected signal after passing the low-pass filter is fed to the input of amplifier 6. According to the proposed device, As the latter, a normalizing amplifier is used here, which can simultaneously carry out amplification and scaling of the input signal of the microcontroller 7. In the microcontroller, e of the input analog signal is first converted to digital and then digital code corresponding to the input analog signal of the microcontroller. The digital code will then be stored using the register until the next conversion of the input signal of the microcontroller is completed. After that, the stored number (code) is transmitted to the microcontroller processor, where the data corresponding to the digital code stored in the microcontroller register is processed. As a result of information processing in the microcontroller, its display (indicator) displays the result of measuring the geometric size (diameter) of the controlled particle.

So, according to the proposed technical solution, by microcontroller processing an information signal about a particle, it is possible to increase the accuracy of measuring the size of a dielectric particle.

Claims (1)

A device for measuring the geometric size of a dielectric particle containing a radiation source, a detector and an amplifier, characterized in that a circulator, a transceiver horn antenna, a low-pass filter and a microcontroller are introduced, the radiation source output being connected to the first arm of the circulator, the second arm of which connected to the transceiver horn antenna, the third arm of the circulator is connected to the input of the detector, the output of the detector through a low-pass filter is connected to the input of the amplifier, the output of which dklyuchen to the input of the microcontroller.