A mist gas generating device and its application

Abstract

The patent belongs to the technical field of particulate matter monitor. The patent discloses a mist gas generating device, which comprises a mist gas generating probe, a liquid sample inlet unit, a gas sample inlet unit and a probe control unit. The device of the patent uses the mist generated by ultrasonic atomization technology to replace the particulate matter powder as the scattering medium of the light scattering particulate matter monitor to realize the calibration of the monitor. Through the control of the atomization probe, the accurate generation of the mist particle size is realized to meet the calibration requirements of the light scattering particulate matter monitor under different application conditions. The tail gas of the device does not need to be treated and can be directly discharged into the atmospheric environment.

Description

Technical Field

[0001] This patent belongs to the field of particulate matter monitoring technology. Background Technology

[0002] Particulate matter, as a significant air pollutant, has become a key focus in the monitoring of ambient air and stationary pollution sources. Studies have shown that particulate matter in ambient air can not only directly enter and deposit in the human respiratory system, but also adsorb and carry some harmful substances dissolved on it. Therefore, monitoring particulate matter concentration is a fundamental means of controlling and improving ambient air quality and protecting public health.

[0003] Light scattering is a commonly used method for monitoring particulate matter concentration. Its small size and low cost have led to its widespread application. Accurate calibration of particulate matter monitoring equipment depends on the accuracy and stability of the particulate matter generation device. Common particulate matter generation devices typically use gas nozzles to spray a mixture of fixed-size particulate matter powder or variable-size grinding rod powder with gas, forming a gas containing a certain concentration of particulate matter. This gas is introduced into the light scattering particulate matter monitoring equipment to be calibrated, and samples are simultaneously taken using methods recognized by Chinese standards, such as beta-ray sampling or manual weighing (or the calibration device is pre-calibrated). By comparing and correcting the results, the light scattering particulate matter monitoring equipment is calibrated.

[0004] The uniformity of particulate powder produced by the methods described above is affected by various factors such as material viscosity and gas flow fluctuations; furthermore, particle size can only be roughly adjusted by grinding speed, making precise selection and control impossible. Therefore, particulate calibration devices employing this principle typically require a long stabilization time when calibrating particulate monitoring equipment, and need to average the data collected over the sampling period to reduce the impact of particulate state fluctuations and errors on the calibration results.

[0005] Furthermore, this method requires filtering or adsorbing particulate matter in the exhaust gas during use to prevent environmental pollution. This additional functionality increases the size and cost of the calibration device, as well as its operation and maintenance expenses.

[0006] The particle size of particulate powder is uniform and cannot be adjusted, and it is prone to agglomeration after being exposed to moisture, making it difficult to guarantee the particle size and concentration of dust; although the particle size of powder produced by grinding rods can be adjusted, the particle size consistency is poor.

[0007] Existing calibration devices use particulate powder or rods as scattering media, resulting in exhaust gases containing a large amount of dust that need to be filtered or adsorbed before being released into the atmosphere. In addition, particulate powder is a consumable, and the operation and maintenance of exhaust gas treatment devices also require a large investment of money. Summary of the Invention

[0008] The primary objective of this patent is to provide a mist gas generating device, comprising:

[0009] A droplet gas generating probe is used to generate droplets of a specific size and a specific number from the liquid entering through the liquid injection unit. The droplets are mixed with the gas entering through the gas injection unit to form droplet gas for calibration.

[0010] The liquid injection unit is used to supply the required liquid to the droplet gas generating probe and to measure the mass of liquid consumed by the droplet gas generating probe in real time.

[0011] The gas injection unit is used to provide the required gas to the droplet gas generating probe based on the gas supply data of the calibration device control unit, and at the same time control and measure the gas flow rate flowing through the droplet gas generating probe in real time and feed back the gas flow rate data to the calibration device control unit.

[0012] The probe control unit is used to generate driving voltage and driving frequency operating condition data for the droplet gas generating probe based on particle diameter data and particle concentration data, and to control the driving voltage and driving frequency of the ultrasonic atomizing probe based on the operating condition data.

[0013] Furthermore, the driving voltage and driving frequency operating condition data are based on particle diameter data and particle concentration data. The probe control unit calculates the ultrasonic frequency F that needs to be generated in the droplet gas generating probe according to the particle size formula and calculates the number of droplets according to the concentration formula.

[0014] Furthermore, the particle size formula is as follows:

[0015] D=C(8πT / ρF 2 ) 1 / 3

[0016] Wherein, C is the atomization coefficient, with a value ranging from 0.3 to 0.4, preferably 0.34; D is the droplet diameter; T is the liquid surface tension coefficient; ρ is the liquid density; and F is the ultrasonic frequency.

[0017] Furthermore, the concentration formula is as follows:

[0018]

[0019] Where N is the number of droplets, M is the amount of liquid consumed by the liquid injection unit, m is the mass of a single droplet, ρ is the liquid density, and D is the droplet diameter.

[0020] The second objective of this patent is to provide a monitoring instrument calibration device, comprising:

[0021] A droplet gas generating probe is used to generate droplets of a specific size and a specific number from the liquid entering the liquid injection unit based on the voltage and drive frequency data generated by the probe control unit. The droplets are mixed with the gas entering through the gas injection unit to generate droplet gas for calibration.

[0022] The liquid injection unit is used to provide the required liquid to the droplet gas generating probe and measure the liquid mass data consumed by the droplet gas generating probe in real time; at the same time, it feeds back the liquid mass data to the calibration device control unit.

[0023] The gas injection unit is used to provide the required gas to the droplet gas generating probe based on the gas supply data of the calibration device control unit, and at the same time control and measure the real-time gas flow data through the droplet gas generating probe and feed the gas flow data back to the calibration device control unit.

[0024] The probe control unit is used to generate driving voltage and driving frequency operating condition data of the droplet gas generating probe based on the particle diameter data and particle concentration data of the calibration device control unit. Based on these data, it controls the driving voltage and driving frequency operating conditions of the droplet gas generating probe and feeds back the droplet diameter and droplet number data to the calibration device control unit.

[0025] The calibration device control unit is used to issue parameter commands to the liquid injection unit, gas injection unit and probe control unit and collect their feedback data based on preset particle diameter and particle concentration data; and to control the light scattering particulate matter monitor and collect droplet gas data, and write or send the calculated calibration parameters to the light scattering particulate matter monitor.

[0026] The light scattering particulate matter monitor is used to collect, record, and feed back the data on droplet gas concentration and / or droplet diameter generated by the droplet gas generating probe to the calibration device control unit; and to record the calibration parameters issued by the calibration device control unit.

[0027] Furthermore, the specific particle size and specific number of droplets are determined based on preset particle diameter and particle concentration data. The probe control unit generates driving voltage and driving frequency operating condition data for the droplet gas generating probe. Based on the driving voltage and driving frequency operating condition data, the probe control unit controls the driving voltage and driving frequency operating conditions of the droplet gas generating probe, so that droplets of a specific particle size and specific number are generated when they enter the liquid through the liquid injection unit.

[0028] Furthermore, it also includes a valve body for connecting to a light scattering particulate matter monitor with active sampling function. When the monitor has active sampling function, the valve body is open; when the monitor does not have active sampling function, the valve body is closed.

[0029] This patent also provides a method for calibrating a monitoring instrument, including the following steps:

[0030] A specific number and size of droplets are mixed with gas to form a droplet gas of a specific concentration;

[0031] Collect and record droplet gas data;

[0032] The calibration device control unit compares the preset concentration data with the collected droplet gas data and makes corresponding adjustments and corrections to the light scattering particulate matter monitor.

[0033] Furthermore, the collection and recording of droplet gas data involves the light scattering particulate matter monitor collecting and recording droplet gas data, and then feeding the droplet gas data back to the calibration device control unit.

[0034] Furthermore, the specific number and specific particle size of droplets are generated by the probe control unit based on the droplet requirement data and preset particle size data, which generates the driving voltage and driving frequency condition data of the droplet gas generating probe. The probe control unit controls the droplet gas generating probe based on the driving voltage and driving frequency condition data, so that the liquid entering through the liquid injection unit generates a specific number and specific particle size of droplets.

[0035] Furthermore, the droplet requirement data is calculated by the calibration device control unit based on preset concentration data.

[0036] The apparatus and method of this patent employ ultrasonic atomization technology to generate droplets instead of particulate powder as the scattering medium for a light-scattering particulate matter monitor, thereby calibrating the monitor. By controlling the atomization probe, accurate droplet size generation is achieved to meet the calibration requirements of light-scattering particulate matter monitors under different application conditions. The exhaust gas from the device requires no treatment and can be directly discharged into the atmosphere. Attached Figure Description

[0037] Figure 1 This is a system diagram of the calibration device.

[0038] 1 is the droplet gas generating probe, 2 is the liquid injection unit, 3 is the gas injection unit, 4 is the probe control unit, 5 is the valve body, 6 is the calibration device control unit, and 7 is the light scattering particulate matter monitor. Detailed Implementation

[0039] Example

[0040] Light scattering particulate matter detection technology utilizes the phenomenon of scattering when light interacts with particulate matter. By collecting and detecting the intensity of scattered light in a specific direction, the concentration information of particulate matter can be obtained.

[0041] Ultrasonic atomization technology uses various ultrasonic transducers to convert electrical energy into acoustic energy, which is then applied to the liquid medium to be tested. At the gas-liquid interface, surface tension waves are formed, which break the intermolecular forces of the liquid and cause the liquid to atomize into droplets.

[0042] This patent uses droplets instead of traditional particulate powder as the scattering medium. The exhaust gas emitted by the device does not contain dust, so no exhaust gas treatment equipment is required, and the structure is relatively simple. At the same time, since the device does not require powder or rods, the operation and maintenance costs are relatively low.

[0043] This patent employs ultrasonic atomization technology to convert liquid into droplets with particle sizes in the micrometer and submicrometer range. By controlling the driving voltage and current of the atomization probe, it achieves the selection and stable generation of droplets of different sizes. Simultaneously, by controlling the weight of the liquid sample introduction unit and the flow rate of the gas sample introduction unit, it enables the generation of gas droplets of varying concentrations. The particulate matter monitoring equipment is calibrated through the pipelines within the device.

[0044] This patent provides a novel calibration device and method applicable to light scattering particulate matter monitoring equipment, effectively achieving stable generation of particulate matter of different sizes. Furthermore, the device has low operation and maintenance costs and low material costs, and produces no pollutants during use, requiring no exhaust gas treatment.

[0045] This patent employs ultrasonic atomization technology. By controlling the driving voltage and driving frequency of the atomization probe, droplets of different numbers and sizes are generated. After mixing with gas, droplet gas of different concentrations is obtained and flows into the light scattering particulate matter monitor to be calibrated. By collecting data from each unit in the calibration device and the scattered light intensity signal in the monitor, calibration parameters are calculated and written into the monitor to realize the calibration function.

[0046] A droplet gas generating device, comprising:

[0047] The droplet gas generating probe 1 is used to generate droplets of a specific size and a specific number from the liquid entering through the liquid injection unit 2. The droplets are mixed with the gas entering through the gas injection unit 3 to form droplet gas for calibration.

[0048] The liquid injection unit 2 is used to provide the required liquid to the droplet gas generating probe 1 and to measure the mass of liquid consumed by the droplet gas generating probe 1 in real time.

[0049] The gas injection unit 3 is used to provide the required gas to the droplet gas generating probe 1 according to the gas supply data of the calibration device control unit 6, and at the same time control and measure the gas flow rate flowing through the droplet gas generating probe 1 in real time and feed back the gas flow rate data to the calibration device control unit 6.

[0050] The probe control unit 4 is used to generate driving voltage and driving frequency operating condition data for the droplet gas generating probe 1 based on particle diameter and particle concentration data, and to control the driving voltage and driving frequency of the droplet gas generating probe 1 based on the operating condition data. The driving voltage and driving frequency operating condition data are calculated by the probe control unit 4 based on the particle diameter and particle concentration data, using a particle size formula to calculate the required ultrasonic frequency F in the droplet gas generating probe 1 and a concentration formula to calculate the number of droplets. The particle size formula is: D=C(8πT / ρF) 2 ) 1 / 3 Where C is the atomization coefficient, ranging from 0.3 to 0.4, preferably 0.34; D is the droplet diameter; T is the liquid surface tension coefficient; ρ is the liquid density; and F is the ultrasonic frequency. The concentration formula is: Where N is the number of droplets, M is the amount of liquid consumed by the liquid injection unit, m is the mass of a single droplet, ρ is the liquid density, and D is the droplet diameter.

[0051] A monitoring instrument calibration device, comprising:

[0052] The droplet gas generating probe 1, according to the instructions of the probe control unit 4, generates droplets of a specific size and quantity by controlling the driving voltage and driving frequency of the liquid introduced by the liquid injection unit 2. These droplets mix with the gas introduced by the gas injection unit 3 to generate droplet gas for calibration. The droplet gas flows along the channel between the droplet gas generating probe 1 and the light scattering particulate matter monitor 7. The specific size and quantity of droplets are determined based on preset particle diameter and concentration data. The probe control unit 4 generates driving voltage and driving frequency operating condition data for the droplet gas generating probe 1. The probe control unit 4 controls the driving voltage and driving frequency operating conditions of the droplet gas generating probe 1 based on the driving voltage and driving frequency operating condition data, so that the liquid introduced by the liquid injection unit 2 generates droplets of a specific size and quantity. The droplets are stably mixed with the gas introduced by the gas injection unit 3 to generate droplet gas of the preset particle size and concentration.

[0053] The liquid injection unit 2 is used to provide the required liquid to the droplet gas generating probe 1 and measure the liquid mass consumed by the droplet gas generating probe 1 in real time; at the same time, it feeds back the liquid mass data to the calibration device control unit 6.

[0054] The gas injection unit 3 is used to provide the required gas to the droplet gas generating probe 1 based on the gas supply data of the calibration device control unit 6, and at the same time control and measure the real-time gas flow rate through the droplet gas generating probe 1 and feed back the gas flow rate data to the calibration device control unit 6.

[0055] The probe control unit 4 generates driving voltage and driving frequency operating condition data for the droplet gas generating probe 1 based on the particle diameter and particle concentration data from the calibration device control unit 6. It controls the driving voltage and driving frequency operating conditions of the droplet gas generating probe 1 according to this data and feeds back the droplet diameter and droplet quantity data to the calibration device control unit 6. The driving voltage and driving frequency operating condition data are calculated by the probe control unit 4 based on the particle diameter data from the calibration device control unit 6, using a particle size formula to determine the required ultrasonic frequency F in the droplet gas generating probe 1, and further adjusting the driving voltage and driving current of the droplet gas generating probe 1 to generate the required ultrasonic frequency. Based on the particle concentration data, the probe control unit 4 calculates the droplet quantity according to a concentration formula and controls the flow rate of the gas entering the gas injection unit 3 to generate a specific concentration. The particle size formula is: D = C(8πT / ρF) 2 ) 1 / 3 Where C is the atomization coefficient, ranging from 0.3 to 0.4, preferably 0.34; D is the droplet diameter; T is the liquid surface tension coefficient; ρ is the liquid density; and F is the ultrasonic frequency. When the liquid type is fixed, the surface tension coefficient and liquid density are constants. A formula can be used to establish the relationship between the droplet diameter D and the ultrasonic frequency F. The concentration formula is as follows: Where N is the number of droplets, M is the amount of liquid consumed by the liquid injection unit, m is the mass of a single droplet, ρ is the liquid density, and D is the droplet diameter.

[0056] Valve body 5 is used to connect to a light scattering particulate matter monitor with active sampling function. When the monitor has active sampling function, valve body 5 is open; when the monitor does not have active sampling function, valve body 5 is closed.

[0057] The calibration device control unit 6 is used to issue parameter commands to the liquid injection unit 2, the gas injection unit 3 and the probe control unit 4 based on preset particle diameter and particle concentration data, and to collect their feedback data; by controlling the light scattering particulate matter monitor 7 and collecting droplet gas data, it obtains physical quantities that can reflect changes in particulate matter concentration, and writes the calculated calibration parameters into the light scattering particulate matter monitor 7 to realize the calibration function.

[0058] The light scattering particulate matter monitor 7 is used to collect, record and feed back the concentration data and / or diameter data of the incoming mist droplets to the calibration device control unit 6; and to record the calibration parameters issued by the calibration device control unit.

[0059] A method for calibrating a monitoring instrument includes the following steps:

[0060] The number and concentration of droplets are calculated based on preset particle size and concentration data; the calculation of the number and concentration of droplets is performed by the calibration device control unit 6 based on the preset particle size and concentration data.

[0061] Based on preset concentration data, the gas requirement data is calculated; the calculated gas requirement data is calculated by the calibration device control unit 6 based on the preset concentration data.

[0062] Based on preset concentration data, the required amount of droplets is calculated; the calculation of the required amount of droplets is performed by the calibration device control unit 6 based on the concentration data.

[0063] Based on the required amount of droplets and the preset particle size data, the probe control unit 4 generates the driving voltage and driving frequency condition data of the droplet gas generating probe 1. The probe control unit 4 controls the droplet gas generating probe 1 according to the driving voltage and driving frequency condition data, so that the liquid entering through the liquid injection unit generates a specific number of droplets with a specific particle size.

[0064] The driving voltage and driving frequency operating condition data are based on the particle diameter data of the calibration device control unit 6. The probe control unit 4 calculates the ultrasonic frequency F required by the droplet gas generating probe 1 according to the particle diameter formula, and further adjusts the driving voltage and driving current of the droplet gas generating probe 1 to make the droplet gas generating probe 1 generate the required ultrasonic frequency. Based on the particle size concentration data, the probe control unit 4 calculates the number of droplets according to the concentration formula, controls the flow rate of the gas entering the gas injection unit 3, and generates a specific concentration.

[0065] The particle size formula is:

[0066] D=C(8πT / ρF 2 ) 1 / 3

[0067] Where C is the atomization coefficient, ranging from 0.3 to 0.4, preferably 0.34; D is the droplet diameter; T is the liquid surface tension coefficient; ρ is the liquid density; and F is the ultrasonic frequency. When the type of liquid is fixed, the surface tension coefficient and liquid density are constants, and the formula can establish the correspondence between the droplet diameter D and the ultrasonic frequency F.

[0068] The concentration formula is:

[0069]

[0070] Where N is the number of droplets, M is the amount of liquid consumed by the liquid injection unit, m is the mass of a single droplet, ρ is the liquid density, and D is the droplet diameter.

[0071] The droplet gas generating probe 1 generates a specific number of droplets with a specific particle size;

[0072] A specific number and size of droplets are mixed with the gas entering through the gas injection unit 3 to generate a specific concentration of droplet gas.

[0073] Collecting and recording droplet gas data; the collection and recording of droplet gas data refers to the light scattering particulate matter monitor 7 collecting and recording the incoming droplet gas data and feeding the droplet gas data back to the calibration device control unit 6.

[0074] The calibration device control unit 6 compares the preset concentration data with the collected droplet gas data and makes corresponding adjustments and corrections to the light scattering particulate matter monitor 7.

[0075] This patented system and method uses droplets generated by ultrasonic atomization technology to replace particulate powder as the scattering medium in a light-scattering particulate matter monitor for calibration. By controlling conditions such as the driving voltage and frequency of the atomization probe, accurate droplet size generation is achieved to meet the calibration requirements of light-scattering particulate matter monitors under different application conditions. The exhaust gas from the device requires no treatment and can be directly discharged into the atmosphere. This patented system and method can achieve accurate droplet size generation and precise control of droplet gas concentration.

Claims

1. A method for calibrating a monitoring instrument, characterized in that, Includes the following steps: A specific number and size of droplets are mixed with gas to form a droplet gas of a specific concentration; Collect and record droplet gas data; The calibration device control unit compares the preset concentration data with the collected droplet gas data and makes corresponding adjustments and corrections to the light scattering particulate matter monitor. The acquisition and recording of droplet gas data refers to the light scattering particulate matter monitor acquiring and recording droplet gas concentration data and / or droplet diameter data, and feeding the droplet gas data back to the calibration device control unit; The droplets are generated by the probe control unit controlling the droplet-generating gas generating probe to generate droplets based on the driving voltage and driving frequency condition data of the probe control unit. The specific number and specific particle size of droplets are generated by the probe control unit from the liquid entering through the liquid injection unit, based on the droplet requirement data, preset particle size data, driving voltage and driving frequency condition data of the droplet generating gas generating probe of the probe control unit. The droplet requirement data is calculated by the control unit of the calibration device based on preset concentration data. The specific particle size formula is as follows: ; Where C is the atomization coefficient, ranging from 0.3 to 0.4, D is the droplet diameter, T is the liquid surface tension coefficient, ρ is the liquid density, and F is the ultrasonic frequency; The specific quantity formula is: ; Where N is the number of droplets, M is the amount of liquid consumed by the liquid injection unit, m is the mass of a single droplet, ρ is the liquid density, and D is the droplet diameter; The calibration method for the monitoring instrument does not produce any pollutants during use, and the exhaust gas does not contain dust, so no exhaust gas treatment is required.

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