RU2801784C1 - Method for control of content of mechanical impurities in aerosols and liquids and device of optical cell for its implementation - Google Patents

Abstract

FIELD: measurement equipment.

SUBSTANCE: optical analysis of fluid media and method for controlling the content of mechanical impurities in aerosols and liquids. The method includes passing a controlled fluid medium, which is an aerosol or liquid, through a sampling path capillary located inside a closed hermetic cell and forming a laser radiation beam crossing the capillary. The laser radiation scattered by mechanical impurities of the fluid is collected by a spherical mirror located at an angle to the direction of the laser radiation and directed to a semiconductor detector located opposite the mirror. The direct laser radiation transmitted outside the capillary is absorbed by a black body placed in the cell on the side of the capillary opposite to the side where the semiconductor laser is located.

EFFECT: possibility of monitoring the content of mechanical impurities in aerosols and liquids in real time, determining concentration of particles, as well as improving the accuracy of measurements.

8 cl, 2 dwg

Description

The claimed group of inventions relates to studies of a fluid medium using optical means, in particular, to methods and means for controlling the content of mechanical impurities in aerosols and liquids.

A known method of measuring the counting and mass concentration of aerosol particles, implemented in optoelectronic aerosol complex. The device contains an optical unit connected in series, a photosensitive receiver, a particle counter, circuits for converting the counting concentration of aerosol particles into a mass concentration and circuits for comparing the measured mass concentration of aerosol particles with a given MPC value, a circuit for generating sound and light signals (RU 179118).

The disadvantage of this implementation is the inability to measure in real time the counting concentration of particles in the liquid.

A known method for measuring the counting concentration of particles in a liquid, implemented in an optical particle counter. This device has a laser cavity with an enlarged aperture that generates laser light, an input jet that provides liquid flow to the particle detection area inside the laser cavity, the input jet has a jet inlet; an optical detection unit arranged to collect light scattered from the particles, with a detection area to obtain an output signal indicative of the particles; and an optical barrier package positioned to reduce noise compared to an enlarged aperture system without an optical barrier package for fluid flow rates greater than or equal to about 0.1 cubic feet per minute. The optical barrier complex prevents the laser beam from illuminating turbulent eddy currents that occur on the inner walls of the inlet jet. The optical barrier complex includes one or more physical apertures, one or more optical stops, or both, which are positioned to prevent laser beam illumination of eddy currents (US 6903818).

The disadvantage of this method is the impossibility of measuring with its help in real time the counting and mass concentration of particles in aerosols.

There is known a method for measuring the counting concentration of aerosol particles, implemented in a particle counter, including: a multi-flow cell with flow channels located in the first direction and having a section including a detection area for detecting a particle formed when the flow channel is irradiated with emitting light; a light receiving optical system configured to receive emitted light generated by a particle contained in the sample fluid flowing in at least one flow channel and passing through the detection area; an optical axis moving unit, configured to move the emitted light optical axis and the emitted light optical axis in the first direction; and a counter configured to count particles for each particle size based on the intensity of emitted light (US 11262284).

The disadvantage of this method is the impossibility of using it in technical means designed to measure in real time the mass concentration of aerosol particles, as well as the counting concentration of particles in a liquid.

It is known to use an optical sensor as a sensor for the mass concentration of aerosol particles. To ensure that different degrees of contamination of the optical particle sensor can be detected by the sensor and can be taken into account, the optical particle sensor identifies individual particles at low particle concentrations up to 1000 particles/cm ³ (US 10488313).

A known method for measuring the counting concentration of aerosol particles, implemented in a wide-range particle counter. This device has sections that separately detect large and small particles in the aerosol. Large particles are counted and measured in an optical particle counter. Fine particles are classified using a differential mobility analyzer for size determination and then passed through an evaporator and condenser and also counted (US 6639671).

The disadvantage of this method is the inability to use it to measure in real time the countable concentration of particles in the liquid.

A known method for measuring the counting concentration of aerosol particles, implemented in a device that includes a sealed detection chamber, a gas path and a light path, and the gas path contains a gas tube for sample supply and a receiving gas tube, which are located coaxially and rigidly connected to the sealed detection chamber; the light path contains a light source that emits divergent rays; the incident lens set and the apertured curved mirror are successively arranged along the direct direction of rays emitted from the light source, and both the incident lens set and the curved mirror are fixedly connected to the sealed detection chamber; the focal point of the curvilinear mirror is located at the intersection of the light flux. path and gas path, and the curvilinear mirror is equipped with a device for lateral collection and detection of light; the sample gas pipe is provided with an outer sleeve with a sheathed flow pipe coaxial with the sample gas pipe, and an annulus is formed between the sheathed flow pipe and the sample gas pipe to allow passage of pure sheath gas; the outlet end of the annulus is parallel and aligned. to the outlet end of the gas outlet pipe for supplying the sample; and the outlet end of the jacketed flue pipe is connected to the nozzle. The invention can effectively prevent the diffusion of sample gas streams, thereby increasing the detection accuracy (CN 101639435).

The disadvantage of this method is the impossibility of using it to measure in real time the number concentration of particles in a liquid, as well as the mass concentration of aerosol particles.

A known method for measuring the counting and mass concentration of aerosol particles, implemented in an optical sensor, which determines the speed of particles passing through the particle detection zone, and, consequently, the gas flow rate, both by the measured time of flight of individual particles, and by the magnitude of the scattered light intensity peaks . This is used to determine particle concentration and can be used to control an optional fan (US10900894).

The disadvantage of this method is the inability to use it to measure in real time the countable concentration of particles in the liquid.

A known method for controlling the quantitative content of mechanical impurities in a liquid, which consists in the fact that the flow is passed, maintaining a constant flow rate, through a system of filtering partitions with successively decreasing pore sizes, while measuring the pressure in front of each filtering partition and the pressure behind it, calculated on the basis of a change in the difference pressure, the hydraulic resistance of the filtering partition over time, then, according to the data obtained, the degree of clogging of the filtering partition is determined by comparing with the available calibration data showing the change in the hydraulic resistance of the filtering partition depending on the content of mechanical impurities, and based on these data, the amount of mechanical impurities of a certain size and / or determine the change in the amount of mechanical impurities of a certain size by pumping time. It is also known a device for controlling the quantitative content of mechanical impurities in liquid hydrocarbon fuel, containing a system of filtering partitions with successively decreasing pore sizes, pressure sensors installed in front of each filtering partition and behind it, as well as an analytical recorder unit associated with pressure sensors, characterized in that that the analytical unit recorder contains a microprocessor, including comparators, and a memory unit containing previously obtained calibration data on the relationship between the hydraulic resistance and the weight amount of particles retained by each filter partition, moreover, the analytical unit recorder is equipped with a program that makes it possible to calculate the change in the hydraulic resistance of each filtering partition in time depending on the nominal size of pores or cells and the fractional composition of the particles, which calculate the concentration of particles and their fractional distribution in the liquid flow at each controlled section of the technological scheme of fuel purification, the inputs of the microprocessor are connected to the outputs of the pressure sensors and the output of the memory block, and the output of the microprocessor with the input of the memory block and with the input of the display unit containing a digital display capable of displaying on the screen data on the weight amount of mechanical impurities on each filter partition (RU 2563813).

The disadvantages of this group of inventions are low accuracy, low productivity and high labor intensity.

Also known is a method for controlling the content of mechanical impurities and a measuring device for determining the size and number of particles in a liquid has an optical system located between the lighting device and the camera so that light rays with different wavelengths fall to the depth of the measured volume. The device has a measuring cell with a measuring volume into which a liquid containing particles is supplied. The lighting device emits light towards the measured volume, and the camera captures an image of the volume. An optical system located between the lighting device and the camera causes light rays with different wavelengths to fall in different focusing planes (f1-f3) to the depth of the volume. The camera combines the images of the focus planes into one common plane image, and the estimator determines the particles in the images of the focus planes. Independent claims are included for a method for determining the size and number of particles in a liquid. Thus, the device comprises a measuring cell through which a medium containing particles passes, and a lighting device for illuminating the measuring volume, as well as a camera for capturing an image of the measuring volume and an evaluation unit for evaluating the image obtained with the camera and determining the particles (DE 102011006033 , prototype).

This technical solution has two main disadvantages: the impossibility of working with aerosol media, as well as high measurement errors (about 20-25%). The error is caused by the use of a camera as a detector, as well as the use of a lamp as a radiation source.

The technical problem to be solved by the present technical solution is to expand the arsenal, eliminate deficiencies and increase the efficiency of such technical means that provide real-time control of the content of mechanical impurities in aerosols and liquids.

The technical result achieved through the use of the claimed group of inventions is to create an alternative method and design of the measuring cell that implements real-time control of the content of mechanical impurities in aerosols and liquids and the counting concentration of particles in the liquid, as well as increasing the accuracy of measurements.

The essence of the invention in terms of the method for controlling the content of mechanical impurities in aerosols and liquids lies in the fact that it provides for the passage of a controlled fluid medium, which is an aerosol or liquid, through a section of the sampling tract located inside a closed sealed cell, the formation of radiation crossing the sampling tract, the collection of radiation , dispersed by mechanical impurities of the fluid medium and control of the content of mechanical impurities, moreover, the controlled fluid medium, which is an aerosol or liquid, is passed through the capillary of the sampling tract located inside the closed hermetic cell, the formation of a beam of laser radiation by means of a laser crossing the capillary, the collection of laser radiation, the fluid medium scattered by mechanical impurities in the capillary, on a spherical mirror located at an angle to the direction of laser radiation and directing the beam collected by it to a semiconductor detector located opposite to the mirror, with simultaneous absorption of direct laser radiation transmitted outside the capillary using a black body placed in the cell from the side capillary, opposite to the side where the semiconductor laser is placed.

Preferably, the formation of the laser radiation beam is carried out using a semiconductor laser with a wavelength of 632 nm.

Preferably, the scattered laser radiation is collected on a spherical mirror located at right angles to the direction of the laser radiation.

Preferably, sampling is performed using an on/off control valve included in the sampling path with the ability to operate the cell with different fluids.

The essence of the invention in terms of the device of the optical cell for implementing the above method lies in the fact that it contains a section of the sampling tract located inside the closed sealed cell, means for generating radiation crossing the sampling tract, means for radiation scattered by mechanical impurities of the fluid and means for controlling the content of mechanical impurities, moreover, it contains a capillary of the sampling path located inside a closed sealed cell, a laser for forming a beam of laser radiation crossing the capillary, a semiconductor detector of mechanical impurities, a spherical mirror located at an angle to the direction of laser radiation with the possibility of collecting laser radiation scattered by mechanical impurities of the fluid in the capillary , and directing the beam collected by it to a semiconductor detector of mechanical impurities, located opposite to the mirror, and a black body, made with the possibility of absorbing direct laser radiation passing outside the capillary and placed in the cell on the side of the capillary, opposite to the side of the semiconductor laser.

Preferably, the laser is in the form of a 632 nm semiconductor laser.

Preferably, the spherical mirror is at right angles to the direction of the laser light.

Preferably, the device is provided with a sampling means in the form of a distributing valve included in the sampling path so that the cell can operate with different fluids.

A study of the state of the art of identical methods and devices of the optical cell used in devices for monitoring the content of mechanical impurities in aerosols and liquids was not found.

In FIG. 1 shows a diagram of a cell in section, Fig. 2 is a diagram of an optical cell for implementing a method for controlling the content of mechanical impurities in aerosols and liquids, external view.

In the drawing of FIG. 1 marked:

1 - Semiconductor laser with a wavelength of about 632 nm; 2 - spherical mirror; 3 - capillary; 4 - black body; 5 - semiconductor detector; 6 - channels for blowing the laser and detector with clean air.

In the drawing of FIG. 2 marked:

7 - optical cell (case); 1 - semiconductor laser; 8 - sampling tract; 9 - distribution valve.

The device of the optical cell contains a section of the sampling path 8 located inside the closed sealed cell, means for generating radiation that crosses the sampling path 9, means for radiation scattered by mechanical impurities of the fluid, and means for controlling the content of mechanical impurities.

The cell 7 contains a capillary 3 of the sampling path 8 placed inside the closed hermetic cell 7, a semiconductor laser 1 for forming a beam of laser radiation crossing the capillary 3, a semiconductor detector 5 of mechanical impurities (a semiconductor photodiode instead of a camera), a spherical mirror 2 (segment of a spherical mirror) located at an angle to the direction of laser radiation with the possibility of collecting laser radiation scattered by mechanical impurities of the fluid medium in the capillary 3, and directing the beam collected by it to a semiconductor detector 5 of mechanical impurities located opposite to the mirror 2, and a black body 4, made with the possibility of absorbing the passed outside the capillary 3 of direct laser radiation and placed in cell 7 on the side of capillary 3, opposite to the side of placement of semiconductor laser 1.

Laser 1 is made in the form of a semiconductor laser with a wavelength of about 632 nm.

The spherical mirror 2 is located at a right angle to the direction of the laser radiation.

The device is equipped with a sampling device in the form of a distribution valve 9 included in the sampling path 8 with the ability to operate the cell with different fluids.

The method and operation of the optical cell device for implementing the method for controlling the content of mechanical impurities in aerosols and liquids are carried out as follows.

The semiconductor laser 1 forms a beam passing through the capillary 3 through which the particles contained in the air or liquid move. The light scattered by them is collected on a spherical mirror 2 and falls on a semiconductor detector 5. Direct laser radiation falls on a black body 4, where it is absorbed and does not introduce additional errors into the measurement result. After the measurement, in order to clean the cell from the residual concentration of particles, the cell (laser 1 and detector 5) is cleaned through the channels 6 of the blower 6 to improve the measurement accuracy and reduce the random component of the measurement uncertainty.

In accordance with FIG. 2, the possibility of using this cell in the process of measuring the parameters of particles, both in aerosols and in liquids, is due to the presence of a distribution valve 9. The correct operation of cell 7 with different media is ensured by the system for supplying air to cell 7 through a filter (not shown) in reverse direction.

The measurement results can be transmitted to a processing optical-electronic aerosol complex (not shown) that monitors the content of mechanical impurities in a controlled fluid medium. Such a complex may include an analytical recorder connected to pressure sensors, as well as a microprocessor including comparators, and a memory unit. The specified analytical unit recorder is equipped, for example, with a program that makes it possible to calculate the fractional composition of particles, according to which the concentration of particles and their fractional distribution in the fluid flow are calculated, and the output of the microprocessor with the input of the memory block and with the input of the display unit containing a digital display having the ability to display on the screen integral data on the amount of mechanical impurities detected in real time.

The technical result is achieved due to the use of a semiconductor laser with a wavelength of about 632 nm as an illuminator in the design of the cell. Also, for aerosol implementations, the cell is blown to clean it from dust. Additionally, to ensure the possibility of taking both liquid and aerosol samples, its design provides for the presence of a distribution valve 9. The correct operation of the cell with different media is ensured by the air supply system to the cell 7 through the filter in the opposite direction.

This group of inventions (method and cell design) makes it possible to measure the number concentration of particles in a liquid, the number concentration of aerosol particles, the mass concentration of aerosol particles without the need to develop additional devices, and also significantly reduces the cost and simplifies the process of production, operation and maintenance of measuring instruments, which include it enters through the standardization of components.

This group of inventions (method and cell design) makes it possible to provide measurement errors at the level of 10-15%, in particular, due to the use of a semiconductor laser with a wavelength of about 632 nm as an illuminator in the cell design. Also, for aerosol implementations, the cell is blown to clean it from dust.

The technical result is achieved through the use of a semiconductor laser with a wavelength of about 632 nm as an illuminator in the cell design, as well as the use of a semiconductor photodiode instead of a camera. Also, for aerosol implementations, the cell is blown to clean it from dust. Additionally, to ensure the possibility of alternate sampling of both liquid and aerosol samples, its design provides for the presence of a distribution valve.

Thus, as a result of the implementation of the claimed group of technical solutions, an original method and device for controlling the content of mechanical impurities in aerosols and liquids is being created. An increase in the accuracy and efficiency of such technical means has been provided.

Claims (10)

1. A method for controlling the content of mechanical impurities in aerosols and liquids, including passing a controlled fluid medium, which is an aerosol or liquid, through a section of the sampling tract located inside a closed sealed cell, generating radiation that crosses the sampling tract, collecting radiation scattered by mechanical impurities of the fluid medium, and control of the content of mechanical impurities, characterized in that the section of the sampling path located inside the closed sealed cell, through which the controlled fluid is passed, is made in the form of a capillary, the radiation is formed using a semiconductor laser, the beam of which crosses the capillary, the collection of laser radiation scattered by mechanical impurities of the fluid in the capillary , is performed by a spherical mirror located at an angle to the direction of laser radiation and directing the radiation collected by it to a semiconductor detector located opposite the mirror, direct laser radiation passing outside the capillary is absorbed by a black body placed in the cell on the side of the capillary, opposite to the side of the semiconductor laser. 2. The method according to claim 1, characterized in that the formation of a laser radiation beam is carried out using a semiconductor laser with a wavelength of 632 nm. 3. The method according to any one of paragraphs. 1, 2, characterized in that the collection of scattered laser radiation is carried out on a spherical mirror located at right angles to the direction of laser radiation. 4. The method according to any one of paragraphs. 1, 2, characterized in that sampling is performed using a two-position control valve included in the sampling path with the ability to operate the cell with different fluids. 5. The device of the optical cell for implementing the method according to any one of paragraphs. 1-4, containing a section of the sampling tract located inside the closed sealed cell, means for generating radiation crossing the sampling tract, a means for collecting radiation scattered by mechanical impurities of the fluid, and a means for controlling the content of mechanical impurities, characterized in that the section of the sampling path located inside the closed sealed cell is made in the form of a capillary, the means for generating radiation is a semiconductor laser designed to form a beam of laser radiation crossing the capillary, the means for controlling the content of mechanical impurities is a semiconductor detector, the means for collecting radiation is made in in the form of a spherical mirror located at an angle to the direction of laser radiation with the possibility of collecting laser radiation scattered by mechanical impurities of the fluid medium in the capillary, and directing the collected radiation to a semiconductor detector located opposite the mirror, the device additionally contains a black body configured to absorb the radiation passed outside the capillary direct laser radiation and placed in the cell on the side of the capillary, opposite to the side of the semiconductor laser. 6. The device according to claim 5, characterized in that the laser is made in the form of a semiconductor laser with a wavelength of 632 nm. 7. The device according to any one of paragraphs. 5, 6, characterized in that the spherical mirror is located at right angles to the direction of laser radiation. 8. The device according to any one of paragraphs. 5, 6, characterized in that it is equipped with a sampling device in the form of a distribution valve included in the sampling path with the ability to operate the cell with different fluids.