Dust concentration control system and method based on dust descending model

Abstract

According to the dust concentration control system and method based on the dust descending model, a fan and an air extracting pump are arranged, the fan and the air extracting pump are controlled to work according to the detected difference value between the dust concentration in a blending device and the target dust concentration in combination with the dust descending model, and then the dust concentration in the blending device is controlled; the dust falling model stores the corresponding dust concentration changes of the sucking pump and the fan under different starting conditions under different dust target concentration values, the working modes of the controlled fan and the sucking pump can be correspondingly adjusted according to the dust falling model, the time spent on reducing the dust concentration is shortened, and the efficiency of reducing the dust concentration is improved. Therefore, the stabilization time of the dust concentration in the uniform mixing box is shortened.

Description

Technical Field

[0001] The present invention belongs to the technical field related to dust metering, and in particular relates to a dust concentration control system and method based on a dust drop model. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] The existing dust generating device in the laboratory is mainly composed of dust generating device, mixing device, sampling device and other parts. The dust is brought into the mixing box by high-pressure airflow, and the vacuum pump promotes the settling and mixing of the dust in the mixing box. The standard dust equipment or the dust equipment to be tested is sampled through the sampling port, and the dust concentration can be transferred by comparison method or filter membrane weighing method.

[0004] The general dust concentration control method is to use the concentration at the sampling port as feedback to adjust the dust intake, thereby controlling the dust concentration in the mixing box. The main reason for the increase in concentration is that new dust enters the mixing box. Generally, the dust concentration can be higher than the overshoot concentration of the target concentration within a dozen or tens of seconds, and then the dust concentration slowly drops to the target concentration by natural sedimentation. The main reasons for the decrease in dust concentration are: extraction by the inspected equipment and the standard equipment; adsorption by the box; interaction between dust such as agglomeration, etc., leading to a decrease. Some control methods will reduce the amount of dust intake when the dust concentration is close to the target concentration. However, due to the physical properties of dust, there may be dust agglomeration, lack of powder, etc. during the dust intake process, resulting in uneven powder intake, so the overshoot and then reduction adjustment mode is common. Usually, the dust concentration in the mixing box stabilizes for 20 minutes to 40 minutes. If the target concentration value is reduced in subsequent experiments, such as from 80% of the range to 20% of the range, it will still take a lot of time to wait for the dust concentration to drop.

[0005] Therefore, how to control the dust concentration so that it can reach the target dust concentration quickly and stably, save waiting time, compensate for dust agglomeration, powder shortage and other situations that occur during the dust intake process, and timely control the dust concentration to keep it stable is a problem that needs to be solved at present. Summary of the invention

[0006] In order to overcome the above-mentioned deficiencies of the prior art, the present invention provides a dust concentration control system and method based on a dust drop model, which shortens the time taken for dust concentration reduction, thereby shortening the stabilization time of dust concentration in a mixing box.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a dust concentration control system based on a dust drop model, comprising:

[0009] Dust generating device;

[0010] a mixing device, connected to the dust generating device, and used for mixing the dust delivered by the dust generating device with air;

[0011] A fan, installed in the mixing device, is used to control the mass of dust adsorbed and agglomerated at different dust concentrations;

[0012] An air pump connected to the mixing device and used to control the dust quality in the mixing device;

[0013] A dust meter, arranged at the sampling port of the mixing device, for measuring the dust concentration in the mixing device;

[0014] A control unit, which is configured to: control the dust generating device to stop working when the dust concentration in the mixing device measured by the dust meter reaches a target dust concentration setting value; when the dust concentration in the mixing device begins to decrease, control the operation of the fan and the vacuum pump based on the difference between the current dust concentration in the mixing device and the target dust concentration value, combined with a dust reduction model; wherein the target dust concentration setting value is less than the target dust concentration value; the dust reduction model stores the dust concentration changes and dust concentration stability of the vacuum pump and the fan under different start-up conditions under different dust target concentration values.

[0015] In a second aspect, the present invention provides a dust concentration control method based on a dust drop model, characterized in that the method comprises:

[0016] A dust generating device is used to provide dust into the mixing device;

[0017] When the dust concentration in the mixing device measured by the dust meter reaches a target dust concentration setting value, controlling the dust generating device to stop working;

[0018] When it is detected that the dust concentration in the mixing device begins to decrease, the working mode of the fan in the mixing device is controlled according to the difference between the current dust concentration in the mixing device and the target dust concentration value, combined with the dust reduction model, and the working mode of the vacuum pump connected to the mixing device is controlled; wherein the target dust concentration setting value is less than the target dust concentration value; the dust reduction model stores the corresponding dust concentration changes and dust concentration stability of the vacuum pump and the fan under different starting conditions under different dust target concentration values.

[0019] One or more of the above technical solutions have the following beneficial effects:

[0020] In the present invention, a fan and an exhaust pump are provided. The operation of the fan and the exhaust pump is controlled according to the difference between the detected dust concentration in the mixing device and the target dust concentration in combination with the dust reduction model, thereby controlling the dust concentration in the mixing device; the dust reduction model stores the corresponding dust concentration changes and dust concentration stability under different starting conditions of the exhaust pump and the fan under different dust target concentration values, and can adjust the working mode of the controlled fan and exhaust pump accordingly according to the dust reduction model, thereby shortening the time taken for the dust concentration to be reduced, thereby shortening the stabilization time of the dust concentration in the mixing box.

[0021] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0023] Figure 1 It is a graph showing the change of dust concentration over time;

[0024] Figure 2 This is a schematic diagram of a dust measurement and verification control system in Embodiment 1 of the present invention;

[0025] In the figure, 1. dust generating device, 2. mixing device, 3. first sampling port, 4. second sampling port, 5. standard dust monitor, 6. inspected dust monitor, 7. top vacuum pump, 8. bottom vacuum pump, 9. fan, 10. air source control valve, 11. air source, 12. first flow meter, 13. second flow meter, 14. control unit, 15. host computer. DETAILED DESCRIPTION

[0026] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0027] It should be noted that the terms used herein are for describing specific embodiments only and are not intended to be limiting of exemplary embodiments according to the present invention.

[0028] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0029] Embodiment 1

[0030] This embodiment discloses a dust concentration control system based on a dust drop model, including:

[0031] Dust generating device 1;

[0032] A mixing device 2, connected to the dust generating device 1, and used for mixing the dust delivered by the dust generating device 1 with air;

[0033] A fan 9 is installed in the mixing device 2 and is used to control the mass of dust adsorbed and agglomerated at different dust concentrations;

[0034] A top vacuum pump 7 and a bottom vacuum pump 8 are respectively connected to the mixing device 2 to control the dust quality in the mixing device 2;

[0035] A dust meter 5, arranged at the sampling port of the mixing device 2, for measuring the dust concentration in the mixing device 2;

[0036] A flow meter 12, arranged at the sampling port 3 of the mixing device 2, for measuring the gas flow through the sampling port 3;

[0037] A flow meter 13, arranged at the sampling port 4 of the mixing device 2, for measuring the gas flow at the sampling port 4;

[0038] The control unit 14 is configured to: control the dust generating device to stop working when the dust concentration in the mixing device measured by the dust meter reaches the target dust concentration setting value; when the dust concentration in the mixing device begins to decrease, control the operation of the fan and the vacuum pump according to the difference between the current dust concentration in the mixing device and the target dust concentration value, combined with the dust reduction model; wherein the target dust concentration setting value is less than the target dust concentration value; the dust reduction model stores the dust concentration changes and dust concentration stability of the vacuum pump and the fan under different start-up conditions under different dust target concentration values.

[0039] This embodiment can control the dust falling speed by using a combination of a fan and an exhaust pump; by constructing a dust falling model under different dust concentrations, the time taken for the dust concentration to decrease is shortened, thereby shortening the stabilization time of the dust concentration in the mixing box; at the same time, by controlling the fan and the exhaust pump, compensation is made for dust agglomeration, powder shortage and the like that occur during the dust intake process, and the dust concentration is controlled in time to remain stable.

[0040] The control unit controls the opening and closing of the fan and the vacuum pump and the intensity of operation according to the host computer's instructions, controls the opening and closing of the air source control valve according to the host computer's software instructions, collects the flow meter signal and transmits it to the host computer software,

[0041] The upper computer software communicates with the control unit, obtains the actuator status and sends control instructions to control the actuator. The actuator includes a fan, an air pump and an air source control valve. It obtains the current flow at the sampling port and communicates with the standard dust meter to obtain the current dust concentration information.

[0042] The initial dust mass M in the mixing box can be calculated based on the maximum concentration in the mixing box after dust generation and the volume of the mixing box. 初始 ; Arrange multiple fans in the mixing box to promote the adsorption and aggregation of dust in the box. By controlling the fan speed, the dust mass M adsorbed and aggregated at different dust concentrations can be controlled. 吸附团聚 ; Arrange multiple vacuum pumps in the mixing box. By controlling the flow rate of the vacuum pump, the dust mass M removed by the vacuum pump can be controlled and calculated. 抽气泵抽走 The dust mass M removed by sampling can be calculated through the dust meter concentration at the sampling port and the sampling flow rate of the two sampling ports. 采样抽走 .

[0043] Dust concentration at the sampling port ρ 采样口 The following mathematical model can be established:

[0044]

[0045] Through the host computer software, the experimenters chose to establish a dust drop model and input basic information about dust generation, including the volume of the mixing box, the type of dust, and the commonly used measurement range.

[0046] The upper computer controls the dust generating device to generate dust, receives and records the dust concentration data from the dust meter at the sampling port. When the dust concentration at the sampling port reaches the target concentration for the first time, the target concentration here is the maximum value of the commonly used measurement range, and the dust generating device stops generating. Due to the further diffusion of dust, the dust concentration at the sampling port continues to increase, and the highest point is the overshoot concentration. When the dust concentration begins to decrease, the 6 air pumps are controlled to open at full flow / medium flow / low flow, and the 6 fans are controlled to run at high speed / medium speed / low speed. Until the dust concentration drops to 100ug / m 3 The upper computer software filters the dust concentration data of the whole process and calculates the characteristic values, which include the average value per second, the concentration change rate per second, and the dust concentration stability per set time period, such as the dust concentration stability every 5s, 10s, and 30s. So far, it can be obtained that the dust generation system has a corresponding relationship between the dust change rate per second and the dust concentration stability every 5s, every 10s, and every 30s under different dust concentration values ​​and different air pump and fan opening conditions. These corresponding relationships constitute the basic model of dust reduction. For example, if the current dust concentration is ρ, in order to reduce it to the target dust concentration ρ 目标If different air pump flow rates and fan speeds are used, the dust drop curve can be predicted based on the existing dust drop model to obtain the predicted time for the dust concentration to drop to the target concentration and the change in dust concentration stability during the drop process. After each actual measurement, the corresponding relationship between the actual dust concentration, air pump and fan start-up conditions, dust change rate per second, and dust concentration stability every 5s, every 10s, and every 30s will be expanded or corrected in the existing dust drop model.

[0047] The experimenter inputs the target dust concentration ρ through the host computer software 目标 , the host computer controls the operation of the dust generating device. When the dust concentration at the sampling port reaches ρ 停止 (ρ 停止 = k·ρ 目标 , (k≤1)), the dust generating device stops generating, and as the dust spreads, the dust concentration in the tank will continue to rise to a value greater than ρ 目标 , reaching ρ max When the dust concentration starts to decrease, the dust reduction model performs corresponding control according to the difference Δρ between the current dust concentration and the target dust concentration.

[0048] When Δρ≥0.3ρ 目标 Without considering the stability of dust concentration, the air pump is fully opened with a large flow rate, and the fan runs at the first speed, that is, high speed, to promote rapid mixing of dust in the mixing box and rapid reduction of dust concentration.

[0049] When Δρ<0.3ρ 目标 , it is necessary to refer to the dust concentration stability and determine the control strategy according to the dust drop model. Specifically, when the dust concentration stability every 5s, every 10s, and every 30s is ≥10%, it indicates that the dust concentration in the mixing box is fluctuating violently. According to the dust concentration drop rate in the dust drop model, the dust concentration stability every 5s, every 10s, and every 30s corresponds to the air pump flow rate and the fan speed. The air pump flow rate or the fan speed is reduced to slow down the rate of drop of the dust concentration; when the dust concentration stability every 5s, every 10s, and every 30s is ≥5% and <10%, it indicates that the rate of drop of the dust concentration in the mixing box is slowing down and the dust concentration has a stable trend. At this time, turn off the air pump and the fan. There is no need to control the dust concentration through additional means. The dust concentration can be reduced by the natural adsorption of dust so that the dust is finally stabilized at the target concentration. The dust concentration stability is controlled within 5%.

[0050] The target concentration is stable. As the experiment progresses, the dust concentration in the mixing box slowly decreases due to the consumption of dust in the mixing box by the sampling equipment during the sampling process, and begins to deviate from the target concentration value. The host computer controls the operation of the dust generating device and turns on the vacuum pump or fan at the same time to slow down the rate of increase of dust concentration.

[0051] When the rate of increase of dust concentration increases suddenly, that is, the current rate of change of dust concentration per second is ≥ the first set multiple of the rate of change of dust concentration in the previous second, such as 2 times, and after the first set time, such as 5s to 10s, the rate of change of dust concentration returns to the level before the change, at this time, the powder may be unevenly fed, and agglomerated dust enters, causing the dust concentration to rise rapidly. Increase the air volume of the air pump or the fan speed to consume this part of the dust in time and reduce the fluctuation of dust concentration. When the rate of increase of dust concentration decreases suddenly, that is, the current rate of change of dust concentration per second is ≤ the second set multiple of the rate of change of dust concentration in the previous second, such as 1 / 2 times, and after the second set time, such as 5s to 10s, the rate of change of dust concentration returns to the level before the change, it is judged that the powder is unevenly fed and there is a shortage of powder. Reduce the air volume of the air pump or the fan speed to reduce the consumption of dust and reduce the fluctuation of dust concentration.

[0052] Embodiment 2

[0053] The purpose of this embodiment is to provide a dust concentration control method based on a dust drop model, including:

[0054] A dust generating device is used to provide dust into the mixing device;

[0055] When the dust concentration in the mixing device measured by the dust meter reaches a target dust concentration setting value, controlling the dust generating device to stop working;

[0056] When it is detected that the dust concentration in the mixing device begins to decrease, the working mode of the fan in the mixing device is controlled according to the difference between the current dust concentration in the mixing device and the target dust concentration value, combined with the dust reduction model, and the working mode of the vacuum pump connected to the mixing device is controlled; wherein, the target dust concentration setting value is less than the target dust concentration value; the dust reduction model stores the corresponding dust concentration changes of the vacuum pump and the fan under different starting conditions under different dust target concentration values.

[0057] In further embodiments, there is also provided:

[0058] An electronic device includes a memory and a processor, and computer instructions stored in the memory and executed on the processor, wherein when the computer instructions are executed by the processor, the method described in Embodiment 1 is performed. For the sake of brevity, no further description is given here.

[0059] It should be understood that in this embodiment, the processor may be a central processing unit CPU, and the processor may also be other general-purpose processors, digital signal processors DSP, application-specific integrated circuits ASIC, off-the-shelf programmable gate arrays FPGA or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0060] The memory may include a read-only memory and a random access memory, and provide instructions and data to the processor. A portion of the memory may also include a non-volatile random access memory. For example, the memory may also store information about the device type.

[0061] A computer-readable storage medium is used to store computer instructions. When the computer instructions are executed by a processor, the method described in embodiment 1 is completed.

[0062] The method in the first embodiment can be directly embodied as a hardware processor, or a combination of hardware and software modules in the processor. The software module can be located in a mature storage medium in the field such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware. To avoid repetition, it will not be described in detail here.

[0063] A computer program product includes a computer program, and when the computer program is executed by a processor, the method described in the first embodiment is implemented.

[0064] The present invention also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer executable instructions, such as instructions included in a program module, which are executed in a device on a real or virtual processor of the target to perform the process / method as described above. Typically, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform specific tasks or implement specific abstract data types. In various embodiments, the functions of program modules can be combined or divided between program modules as needed. Machine executable instructions for program modules can be executed in local or distributed devices. In distributed devices, program modules can be located in local and remote storage media.

[0065] The computer program code for implementing the method of the present invention can be written in one or more programming languages. These computer program codes can be provided to the processor of a general-purpose computer, a special-purpose computer or other programmable data processing device, so that the program code, when executed by the computer or other programmable data processing device, causes the function / operation specified in the flow chart and / or block diagram to be implemented. The program code can be executed completely on a computer, partially on a computer, as an independent software package, partially on a computer and partially on a remote computer or completely on a remote computer or server.

[0066] In the context of the present invention, computer program codes or related data may be carried by any appropriate carrier to enable a device, apparatus or processor to perform the various processes and operations described above. Examples of carriers include signals, computer readable media, etc. Examples of signals may include electrical, optical, radio, acoustic or other forms of propagation signals, such as carrier waves, infrared signals, etc.

[0067] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with this embodiment can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0068] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A dust concentration control system based on a dust drop model, characterized in that: include: Dust generating device; a mixing device, connected to the dust generating device, and used for mixing the dust delivered by the dust generating device with air; A fan, installed in the mixing device, is used to control the mass of dust adsorbed and agglomerated at different dust concentrations; An air pump connected to the mixing device and used to control the dust quality in the mixing device; A dust meter, arranged at the sampling port of the mixing device, for measuring the dust concentration in the mixing device; A control unit, configured to: when the dust concentration in the mixing device measured by the dust meter reaches a target dust concentration setting value, control the dust generating device to stop working; when the dust concentration in the mixing device begins to decrease, control the operation of the fan and the suction pump in combination with a dust drop model according to the difference between the current dust concentration in the mixing device and the target dust concentration value; wherein the target dust concentration setting value is less than the target dust concentration value; The dust reduction model stores dust concentration changes and dust concentration stability corresponding to different dust concentration values ​​and the vacuum pump and the fan under different start-up conditions.

2. A dust concentration control system based on a dust drop model as claimed in claim 1, characterized in that: The control unit is configured to: after detecting that the dust concentration in the mixing device begins to decrease, if the difference between the current dust concentration in the mixing device and the target dust concentration value is not less than a first set threshold value, control the fan to operate at a first speed, and control the vacuum pump to operate in a full flow mode; If the difference between the current dust concentration in the mixing device and the target dust concentration value is less than a first set threshold, the operation of the fan and the vacuum pump are controlled according to the dust drop model.

3. A dust concentration control system based on a dust drop model as claimed in claim 2, characterized in that: The control unit is configured as follows: if the difference between the current dust concentration in the mixing device and the target dust concentration value is less than a first set threshold, and the dust concentration stability is not less than a first stability threshold, the operation of the fan or the air pump is controlled according to the corresponding curves of the dust concentration reduction rate, dust concentration stability, air pump flow rate and fan speed in the dust reduction model to slow down the rate of decrease of the dust concentration.

4. A dust concentration control system based on a dust drop model as claimed in claim 2, characterized in that: The control unit is configured to: turn off the fan and the air pump if the difference between the current dust concentration in the mixing device and the target dust concentration value is less than a first set threshold, and the dust concentration stability is less than a first stability threshold and not less than a second stability threshold; wherein the first stability threshold is greater than the second stability threshold.

5. A dust concentration control system based on a dust drop model as claimed in claim 1, characterized in that: The control unit is configured as follows: when it is determined that the current dust concentration change rate per second is greater than a first set multiple of the dust concentration change rate in the previous second, and after continuing for a first set time, the dust concentration change rate returns to the level before the change, the air pump flow rate is controlled to increase or the fan speed is controlled to increase; when it is determined that the current dust concentration change rate per second is less than a second set multiple of the dust concentration change rate in the previous second, and after continuing for a second set time, the dust concentration change rate returns to the level before the change, the air pump flow rate is controlled to decrease or the fan speed is controlled to decrease.

6. A dust concentration control system based on a dust drop model as claimed in claim 1, characterized in that: A flow meter is arranged on the connection channel between the dust monitor and the sampling port.

7. A dust concentration control system based on a dust drop model as claimed in claim 1, characterized in that: There are multiple air pumps, which are respectively arranged at the top and bottom of the mixing device.

8. A dust concentration control method based on a dust drop model, characterized in that: The method comprises: A dust generating device is used to provide dust into the mixing device; When the dust concentration in the mixing device measured by the dust meter reaches a target dust concentration setting value, controlling the dust generating device to stop working; When it is detected that the dust concentration in the mixing device begins to decrease, the working mode of the fan in the mixing device is controlled according to the difference between the current dust concentration in the mixing device and the target dust concentration value, combined with the dust reduction model, and the working mode of the vacuum pump connected to the mixing device is controlled; wherein the target dust concentration setting value is less than the target dust concentration value; the dust reduction model stores the corresponding dust concentration changes and dust concentration stability of the vacuum pump and the fan under different starting conditions under different dust target concentration values.

9. A dust concentration control method based on a dust drop model as claimed in claim 8, characterized in that: When it is detected that the dust concentration in the mixing device begins to decrease, if the difference between the current dust concentration in the mixing device and the target dust concentration value is not less than a first set threshold value, the fan is controlled to operate at a first speed, and the vacuum pump is controlled to operate in a full flow mode; If the difference between the current dust concentration in the mixing device and the target dust concentration value is less than a first set threshold, the operation of the fan and the vacuum pump are controlled according to the dust drop model.

10. A dust concentration control method based on a dust drop model as claimed in claim 9, characterized in that: If the difference between the current dust concentration in the mixing device and the target dust concentration value is less than the first set threshold, the operation of the fan and the vacuum pump are controlled according to the dust drop model, specifically: If the difference between the current dust concentration in the mixing device and the target dust concentration value is less than the first set threshold, and the dust concentration stability is not less than the first stability threshold, according to the dust concentration decrease rate in the dust decrease model, the dust concentration stability and the corresponding curve of the air pump flow rate and the fan speed, the fan or the air pump is controlled to slow down the rate of decrease of the dust concentration; If the difference between the current dust concentration in the mixing device and the target dust concentration value is less than the first set threshold, and the dust concentration stability is less than the first stability threshold and not less than the second stability threshold, turn off the fan and the air pump; wherein the first stability threshold is greater than the second stability threshold.

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