WO2017181955A1

WO2017181955A1 - Dust concentration detection device and dust concentration detection method

Info

Publication number: WO2017181955A1
Application number: PCT/CN2017/081074
Authority: WO
Inventors: 聂泳忠; 林梅英
Original assignee: 西人马（厦门）科技有限公司
Priority date: 2016-04-22
Filing date: 2017-04-19
Publication date: 2017-10-26
Also published as: CN105784555A

Abstract

A dust concentration detection device and dust concentration detection method. The dust concentration detection device comprises: an electric field generator (110) used to generate an electric field across air to be tested; an electrical signal measurement module (120) connected to the electric field generator (110) and used to detect a change of an electrical signal in a loop where the electric field is located; and a processor (130) used to receive the electrical signal and analyze the change of the electrical signals, thereby acquiring dust mass concentration in the air to be tested.

Description

Dust concentration detecting device and dust concentration detecting method

Technical field

The invention belongs to the technical field of air quality detection, and more particularly relates to a dust concentration detecting device and a dust concentration detecting method.

Background technique

Dust concentration detection is mainly to detect the concentration of dust in the ambient air. Air pollution, also known as air pollution, is defined by the International Organization for Standardization (ISO). Air pollution usually refers to the presence of certain substances in the atmosphere due to human activities or natural processes, showing sufficient concentration to reach sufficient time. This jeopardizes human comfort, health and welfare or the environment.

PM2.5 is a particulate matter suspended in air with a diameter of less than 2.5 microns. Compared with coarser atmospheric particles, PM2.5 has a small particle size, large area, strong activity, and is easy to attach toxic and harmful substances, such as heavy metals and microorganisms, and has a long residence time in the atmosphere and a long transport distance. The impact of atmospheric environmental quality is particularly evident.

The adhesion of PM2.5 is very strong, and the physiological structure of the human body does not have any filtering or blocking ability for PM2.5. Excessive PM2.5 concentration can cause serious damage to the human respiratory system, cardiovascular system, reproductive system and blood system. harm. Accurate, real-time and convenient detection of PM2.5 concentration to remind people of their daily activities is a significant part of the people's livelihood work.

Summary of the invention

In order to understand and evaluate the hazards of dust in the workplace air to workers' health, research on measures to improve dust prevention techniques and evaluate the effectiveness of dust prevention measures. It is necessary to measure the dust concentration. There are two methods for expressing dust concentration: mass method and quantity method. The mass dust concentration is the mass of dust in a unit volume of air, expressed in mg/m ³ . The amount of dust concentration is expressed as the number of dust particles per unit volume of air, expressed in n/m ³ .

Before the 1960s, the maximum allowable concentration of dust in many countries was expressed by quantitative concentration. China, the Soviet Union and other countries use mass concentration. Later, since the progress of silicosis was closely related to the mass concentration of suspended dust, after the 1970s, countries such as the United Kingdom, the United States, and Japan entered the phase of concentration and mass concentration, and countries gradually developed to mass concentrations. The determination of the dust concentration is easier to measure and the determination of the mass dust concentration is more difficult to achieve.

The present application provides a dust concentration detecting device and a dust concentration detecting method capable of measuring a mass concentration value of dust in a gas to be measured.

According to an aspect of the present invention, there is provided a dust concentration detecting apparatus comprising: an electric field generator for generating an electric field in a gas to be measured; an electric signal measuring module connected to the electric field generator for measuring the electric field a change in the electrical signal in the loop; and a processor that receives the electrical signal for analyzing the change in the electrical signal to obtain a mass concentration value of the dust in the gas to be measured.

According to another aspect of the present invention, there is provided a dust concentration detecting method comprising: generating an electric field in a gas to be measured to ionize the gas to be measured; measuring a change in an electric signal in a loop in which the electric field is located; and analyzing the electric The change in signal obtains the mass concentration value of the dust in the gas to be tested.

According to the dust concentration detecting device of the present invention, the dust mass concentration can be automatically collected and directly measured, the device is miniaturized, the power consumption is low, the weight is portable, and the cost is low, and it can be mass-produced and used in the civil or commercial field.

DRAWINGS

The features and advantages of the present invention are more clearly understood from the following description of the accompanying drawings.

Figure 1 is a block diagram showing the structure of an embodiment of a dust concentration detecting apparatus according to the present invention;

Figure 2 is a flow chart showing one embodiment of a dust concentration detecting method according to the present invention;

Figure 3 is a view showing the structure of an embodiment of a dust concentration detecting device according to the present invention;

Figure 4 is a schematic illustration of one embodiment of a trajectory of a charged particle in an electric field in accordance with the present invention;

Figure 5 shows a block diagram of one embodiment of an electric field generator in accordance with the present invention.

Detailed ways

Features and exemplary embodiments of various aspects of the invention are described in detail below. In the following detailed description, numerous specific details are set forth However, it will be apparent to those skilled in the art that the present invention may be practiced without some of the details. The following description of the embodiments is merely provided to provide a better understanding of the invention. The present invention is in no way limited to any of the specific arrangements and methods disclosed herein, but may be modified, substituted, and modified without departing from the spirit of the invention. In the drawings and the following description, well-known structures and techniques are not shown in order to avoid unnecessary obscuring the invention.

A dust concentration detecting device and a dust concentration detecting method according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

Fig. 1 shows a block diagram showing the structure of a dust concentration detecting device according to an embodiment. According to this embodiment, a dust concentration detecting device may include an electric field generator 110 for generating an electric field in a gas to be tested; an electric signal measuring module 120 connected to the electric field generator 110 for measuring a circuit in which the electric field is located The change of the neutral signal; and the processor 130 is coupled to the electrical signal measuring module 120 for analyzing the change of the electrical signal to obtain a mass concentration value of the dust in the gas to be tested. In one embodiment, the electric field generator can be powered by a 12V DC power supply.

Figure 2 is a flow chart showing one embodiment of a dust concentration detecting method in accordance with the present invention. As shown in FIG. 2, in step s201, an electric field is generated in the gas to be measured to ionize the gas to be measured. In s202, the change in the electrical signal in the loop in which the electric field is located is measured. At s203, the change in the electrical signal is analyzed to obtain a mass concentration value of the dust in the gas to be tested. In one example, the electrical signal to be measured can be current or voltage.

In one embodiment, the electric field may be generated by an electrode connected to a high voltage generator that outputs a high voltage to both ends of the electrode, and an overvoltage protection and an overcurrent protection circuit may be provided in the high voltage generator in consideration of safety. . The electrode can be made of carbon fiber, graphite, metal or the like. In the present application, "high voltage" refers to a voltage sufficient to ionize a gas to be measured (for example, ionize a gas to be measured to generate a large amount of electrons), for example, a voltage between 50V and 10,000V.

In one embodiment, the method further comprises filtering the gas to be measured to filter out particles of a predetermined diameter range, for example, filtering particles having a diameter greater than 2.5 microns from the gas to be tested, Used to detect the mass concentration of, for example, PM2.5.

In one embodiment, the step of measuring the change in the electrical signal of the electric field loop can also filter the signal, filter the noise, and reduce noise interference. For example, low-pass filtering is used to eliminate high-frequency interference. Depending on the noise level, filtering is also not possible.

In one embodiment, the step of measuring the change value of the electrical signal of the electric field loop includes amplifying the loop electrical signal, for example, a voltage-dividing bias amplifying circuit can be used to remove the influence of the original electrical signal in the measuring circuit without dust, and amplifying The change in electrical signal caused by the mass concentration of dust.

In one embodiment, the step of measuring the change in the electrical signal of the electric field loop includes performing an A/D conversion of the loop electrical signal.

In one embodiment, the loop includes a resistor connected in series, measuring the voltage across the resistor or the current through the resistor, and calculating the mass concentration of dust in the air.

The electrical signal in the loop has the following functional relationship with the concentration of dust particles:

When there is no fine particles, the charge amount Q across the electrodes and the _electrical current I _measured the expression:

When tiny particles are present, the current and voltage through the resistor can be expressed as:

Wherein, Q is the _electrical charge amount across the electrodes; is the _U-sensing voltage across the resistor; R & lt _measured as a series resistance in the circuit; ends of the U-voltage electrode; K is an empirical constant setting can be made according to the measured data set; d is the distance between electrodes; S is the area across the electrodes; ε ₀ is the absolute dielectric constant of vacuum; relative permittivity [epsilon] _power change;

The relative dielectric constant change rate; ρ is the gas density to be measured, and the current standard air density value can be determined by the air density meter, combined with the current air pressure and temperature, and the measured gas density minus the current standard air density can be used to obtain the test. The mass concentration of dust particles.

3 shows a schematic diagram of one embodiment of a motion trajectory of charged particles in an electric field, in accordance with an embodiment. FIG. 4 shows a schematic structural view of a dust concentration detecting device according to an embodiment. As shown in FIGS. 3 and 4, the electric field generator includes a high voltage generator 301 and an electrode connected to a high voltage generator 301 for releasing electrons in a gas to be tested and capable of releasing a large amount of electrons, a large amount of electrons. Moving from the negative electrode of the electrode to the positive electrode allows the electric field generator and the electrode to form a closed loop. The voltage range generated by the high voltage generator 301 can be set, for example, from 50V to 10000V. In one embodiment, the high voltage generator 301 can generate a negative voltage of 3800 volts in size. By closing the loop, the electrons will migrate to the other end of the electrode under the action of an electric field. During the migration process, electrons are adsorbed on the dust particles in the air, so that the dust particles in the air become charged particles, and migrate under the force of the electric field, resulting in additional work in the electron migration process, and electron migration increases the migration of dust particles. The energy consumed, in the case of dust-free particles, the presence of dust particles can cause the migration of dust particles to increase the energy consumed by electron migration, resulting in changes in the electrical signal in the loop. The electrical signal can include at least one of a current, a voltage, and a capacitance. For example, an increase in the mass concentration of dust in the gas to be tested results in a decrease in the current value in the loop.

In one embodiment, the high voltage electric field can be provided with two plates, and the gas to be tested between the plates and the plates together form a capacitance, and the change of the dust particles of the gas to be tested in the capacitor causes the capacitance. The change of the dielectric constant, by measuring the capacitance value, combined with the relationship between the dielectric constant and the gas concentration to be measured, can analyze the mass concentration of the dust particles.

In one embodiment, the electrical signal measurement module 302 includes a resistor connected in series in the loop through which the loop current change can be converted to a directly measurable voltage change. By measuring the current of the resistor or the voltage across the resistor, the density of the gas to be tested can be calculated, thereby obtaining the corresponding mass concentration of the dust particles in the gas to be tested. The closed loop current drops, and the mass concentration of dust particles affects the loop current. By measuring the loop current change on a closed loop, The value of the mass concentration of the dust in the air is obtained. The resistance value may vary depending on the range of the electric field voltage. In one embodiment, the high voltage generator 301 can generate a negative voltage of 3800 volts, and the resistance of the precision resistor can be selected to be 1 M ohm.

In an embodiment, the electrical signal measurement module 302 may further include an amplification module 304 for amplifying the electrical signal change caused by the change of the dust concentration. For example, the voltage division bias amplification circuit may be used to remove the dust-free electrical signal measurement module 302. The original electrical signal in the circuit affects the electrical signal changes caused by the mass concentration of the dust, thereby increasing the sensitivity of the device. In one embodiment, the high voltage generator 301 can generate a negative voltage of 3800 volts, the resistance of the precision resistor can be selected to be 1 M ohm, and the amplification factor of the amplification module 304 can be selected to be 50 times.

In an embodiment, the electrical signal measurement module 302 may further include an A/D conversion module 305. For example, the analog signal may be sampled by the A/D conversion module 305 and converted into a digital signal, and the digital signal is input to the processor 306 for analysis. Calculation.

In an embodiment, the electrical signal measurement module 302 may further include a filtering module 303. The filtering module 303 may be disposed before the amplification module 304 to filter noise and reduce noise interference. For example, low-pass filtering is used to eliminate high-frequency interference. In one embodiment, the high voltage generator 301 can generate a negative voltage of 3800 volts, the resistance of the precision resistor can be selected to be 1 M Ω, and the amplification factor of the amplification module 304 can be selected to be 50 times, the sampling mode of the A/D converter. When the signal sampling frequency can be 100 Hz, the filtering module 303 can select a low pass filter capable of rejecting high frequency interference above 100 Hz. Depending on the noise level, filtering is also not possible.

In one embodiment, the processor is configured to obtain a current I _detected by the resistor is calculated by _measuring the voltage U across the resistance measured, and the charge amount Q based _electrically across the electrodes, the voltage across the electrode U, electrode distance d, area S across the electrodes, the absolute permittivity of vacuum ε _0, the relative _electrical permittivity [epsilon] change, rate of change in relative dielectric constant

The density of the gas to be tested is calculated to obtain the mass concentration of the dust of the gas to be tested.

Those skilled in the art will appreciate that the processor can be implemented in software, hardware, and/or firmware. For example, in one embodiment, the processor can pass through the process in the information processing device Implemented by sequential instructions, which may be stored in a non-volatile memory of the information processing device and, when executed by one or more processors of the information processing device, cause the information processing device to implement a corresponding amplification module 304, a filtering module 303, an A/D conversion module 305, and a computing module. These program instructions may be included in an executable file or APP that exists in the form of source code, object code, intermediate code, etc., and that can be executed in a compiled or interpreted manner. In another embodiment, the processor may be implemented by a hard-wired circuit, wherein the amplification module 304, the filtering module 303, the A/D conversion module 305, and the processor may be separate and connected circuits, or may be integrated in together.

In an embodiment, the dust concentration detecting device may include a detecting circuit and a processor 306, and the detecting circuit may include a high voltage generator 301, an electrical signal measuring module 302, a filtering module 303, an amplifying module 304, and an A/D conversion module. 305. The signal measured by the signal measurement module 302 is processed by the filtering module 303, the amplification module 304, and the A/D conversion module 305, and the processed digital signal is analyzed by the processor 306 to obtain a mass concentration of the dust.

According to one embodiment, the dust concentration detecting device is further provided with a filter layer for filtering out particles of a predetermined diameter range, and the dust concentration detecting device can check only the concentration of the particulate matter of a specific diameter range.

According to an embodiment, an insulating layer and/or a shielding layer is also provided, which is used to insulate the electric field from the outside, the shielding layer for shielding the electric field from the outside.

Figure 5 shows a simplified block diagram of an electric field generator, in accordance with one embodiment. The electric field generator includes an electrode 501 that is disposed within a gas permeable housing. The outside air can be in contact with the electrode 501 inside the casing through the casing, and the electrode 501 here can be a carbon fiber material or a metal needle. The housing is provided with an insulating layer 502 and/or a shielding layer 503 for insulating the electric field from the outside, the shielding layer for shielding the electric field from the outside. For example, the insulating layer 502 and the shielding layer 503 may be disposed in the housing or in the housing, or may be disposed at the same time or separately. The arrangement may be a bonding, a clamping, or the like. In the above, it may also be arranged outside the casing by means of extrusion, wrapping or the like.

In an embodiment, the housing portion may be cylindrical, the outermost layer may be a copper material as the electromagnetic shielding layer 503, the inner layer may be made of a plastic material as the insulating layer 502, and the inner layer may be distributed on the cylinder. A hole, such as a small hole, may be a small circular hole having a diameter of 1.5 mm. Enter the passage for air.

In one embodiment, the electrode 501 is provided with a filter layer for filtering out particles of a predetermined diameter range, for example, the filter layer is configured to filter out particles having a diameter greater than 2.5 microns, which is also referred to as PM2.5. Fine particulate matter refers to particulate matter having an aerodynamic equivalent diameter of 2.5 microns or less in ambient air. It can be suspended in the air for a long time, and the higher its concentration in the air, the more serious the air pollution. Although PM2.5 is only a small component of the Earth's atmospheric composition, it has an important impact on air quality and visibility. Compared with coarser atmospheric particles, PM2.5 has a small particle size, large area, strong activity, and is easy to attach toxic and harmful substances, such as heavy metals and microorganisms, and has a long residence time in the atmosphere and a long transport distance. The effects of human health and the quality of the atmospheric environment are greater. This can be used to detect the mass concentration value of PM2.5. The filter layer may be a filter paper, a microfiltration membrane of polystyrene, or the like. The filter layer may be disposed in the casing or outside the casing. The installation may be provided on the casing by means of bonding, jamming or the like, or may be arranged outside the casing by extrusion, wrapping or the like.

In one embodiment, the electric field generator can include electrodes spaced a predetermined distance, where the spacing of the electrodes is adjustable. Each electrode 501 can be provided with a tip end, and the spacing between the two ends is required to prevent breakdown and ensure sensitivity.

In one embodiment, the electrodes 501 are disposed at both ends of the housing, and the tip spacing of the electrodes 501 can be adjusted by adjustment members, such as by adjusting the distance of the tips of the electrodes 501.

In one embodiment, for example, the high voltage generator 301 can generate a negative voltage of 3800 volts, the resistance of the precision resistor can be selected to be 1 M ohm, and the tip spacing of the two electrodes 501 can be set to 7 mm.

In one embodiment, the dust concentration detecting device may implement a communication connection with at least one other network element through at least one communication module (which may be a wired communication module or a wireless communication module), and the wireless communication module receives the analysis by the processor. The obtained mass concentration signal is sent to a remote server or a portable mobile client, for example, the measured dust particle concentration value can be uploaded to the remote server or the portable mobile client in real time through the Bluetooth module. Real-time display of shared data, similar wireless communication modules such as infrared and wireless networks can be used to achieve similar communication effects.

It should be noted that in the claims the word "comprising" or "including" does not exclude the An element or component in the claims. The article "a" or "an" or "an"

In addition, it should be noted that the language used in the specification has been selected for the purpose of readability and teaching, and is not intended to be construed or limited. Therefore, many modifications and changes will be apparent to those skilled in the art without departing from the scope of the invention. The descriptions of the present invention are intended to be illustrative, and not restrictive, and the scope of the invention is defined by the appended claims.

Claims

A dust concentration detecting device comprising:

An electric field generator for generating an electric field in the gas to be tested to ionize the gas to be tested;

An electrical signal measurement module coupled to the electric field generator for measuring a change in an electrical signal in a loop in which the electric field is located;

The processor receives the electrical signal for analyzing a change in the electrical signal to obtain a mass concentration value of the dust in the gas to be tested.
The dust concentration detecting device according to claim 1, wherein said electric field generator comprises:

An electrode disposed in the gas to be tested;

a high voltage generator connected to the electrode,

Wherein the electrode releases electrons at a high voltage provided by the high voltage generator.
The dust concentration detecting apparatus according to claim 1, wherein said electric signal comprises at least one of a current, a voltage, and a capacitance.
The dust concentration detecting apparatus according to claim 1, wherein said electric signal measuring module includes a resistor connected in series in said loop.
The dust concentration detecting device according to claim 1, further comprising at least one of the following:

a filtering module, configured to filter the electrical signal to filter out a noise signal in the electrical signal;

An amplification module for amplifying a change of the electrical signal;

An A/D conversion module for converting the electrical signal from an analog signal to a digital signal,

Wherein the processor performs the analysis on the digital signal.
The dust concentration detecting device according to claim 1, wherein said electric field generator An electrode is provided that is spaced apart by a predetermined distance, the spacing of the electrodes being adjustable.
The dust concentration detecting device according to claim 1, further comprising a filtering layer for filtering out particles of a predetermined diameter range of said gas to be measured.
A dust concentration detecting device according to claim 1, further comprising an insulating layer for insulating the electric field from the outside, and/or a shielding layer for opposing said electric field with respect to The outside is shielded.
The dust concentration detecting device according to claim 7, wherein the filter layer is configured to filter out particles having a diameter of more than 2.5 μm.
A dust concentration detecting apparatus according to claim 1, further comprising a wireless communication module that receives a mass concentration signal analyzed by said processor and transmits said quality density signal to a remote server or Portable mobile client.
A method for detecting dust concentration, comprising:

Generating an electric field in the gas to be tested to ionize the gas to be tested;

Measuring a change in an electrical signal in a loop in which the electric field is located;

The change in the electrical signal is analyzed to obtain a mass concentration value of the dust in the gas to be tested.
The dust concentration detecting method according to claim 11, wherein said electric field is generated by an electrode connected to a high voltage generator.
The dust concentration detecting method according to claim 11, further comprising filtering said gas to be measured to filter out particles of a predetermined diameter range.
The dust concentration detecting method according to claim 13, wherein said filtering removes particles having a diameter of more than 2.5 μm from the gas to be tested.